Year 2: Solar Tracking and Energy Use for 2017

Posted on by kent

Last year, I’d been very pleased with the house’s first year performance, but after analyzing the numbers, I’d thought there was still room for improvement.

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With a few tweaks and utilizing our wood stove a bit more, I was looking forward to seeing how we did for 2017 compared to our first year. Let’s find out!

For completeness sake, below are some key stats from my previous 2016 blog post about our energy modelling and actual use:

HOT2000 Predictions:

Annual Space Heating Energy Consumption: 7159 kWh

Annual Domestic Hot Water (DHW) Energy Consumption: 3409 kWh

Annual Appliance Energy Consumption: 8760 kWh

TOTAL = 19,328 kWh/year

PHPP Predictions:

Annual Space Heating Energy Consumption: 7584 kWh

Annual DHW Energy Consumption: 3974 kWh

Annual Appliance Energy Consumption: 11,310 kWh

TOTAL = 22,868 kWh/year

PV Array Predictions (6.2 KW)

PHPP Estimation: 7321 kWh/year

Solar Installer’s Estimation: 9300 kWh/year

Also:

For interest, according to Stats Canada website’s most recent 2011 home energy use data, a Saskatchewan home consumes an average of 30,555 kWh/year (110 GJ), of which electricity for appliance use is 8889 kWh/year (32 GJ).

2016 ACTUAL TOTALS:

Actual Solar PV Generated = 8189 kWh

Actual Household Energy Consumed = 19,000 kWh

Actual Total Energy Used (consumption – PV) = 10,811 kWh

We did pretty darn good in 2016, actually coming in under the estimated values with the exception of the higher end of the solar production (though that is the manufacturer’s estimates so probably these are the “best case scenario” numbers anyway).

So how did we do for 2017?

2017 ACTUAL ENERGY CONSUMPTION AND PV GENERATION:

January: Solar generated = 250 kWh vs. Energy Use = 2979 kWh

  • A dramatic difference no doubt. But I was not surprised given I had 2016 to compare, it’s January in Saskatchewan after all. Still our energy use was less than the previous year (by almost 400 kWh) so we were off to a good start.

February: Solar generated = 378 kWh vs. Energy Use = 1258 kWh

  • This is when I did my experiment. We kept the boiler set at 65°F and tried to burn wood as much as possible. There was a more than 50% drop in energy use (electric) from 2016.

March: Solar generated = 695 kWh vs. Energy Use = 1652 kWh

  • Pretty much the same as 2016. We kept the boiler set a bit high at 68°F (65°F is too cool first thing in the morning!). But it was starting to get warmer this month. Note that we used over 400 kWh more this month then February – due to less wood heat, even though the outdoor temperatures were rising.

April: Solar generated = 736 kWh vs. Energy Use = 1125 kWh

  • April kind of sucked. It was cloudy and not very Spring-like at all. Many days were around the freezing temperature still.

May: Solar generated = 1143 kWh vs. Energy Use = 840 kWh

  • Hot month and hit the net positive energy production one month early as a result.

June: Solar generated = 1092 kWh vs. Energy Use = 708 kWh

  • It was a hot and dry month and I watered the garden nearly every day which uses a fair bit of electricity to run the water pump at the river.

July: Solar generated = 1112 kWh vs. Energy Use = 575 kWh

  • It was really hot again in July. Only 2 or 3 days of rain all month.

August: Solar generated = 982 kWh vs. Energy Use = 643 kWh

  • Almost completely opposite weather to 2016, which was extremely rainy. This month was HOT and DRY.

September: Solar generated = 744 kWh vs. Energy Use = 662 kWh

  • Finally started to become seasonal temperatures in September. But still remained Net Positive for energy use.

October: Solar generated = 555 kWh vs. Energy Use = 771 kWh

  • Last October (2016) was terrible – snowing on October 4th. This October was more normal and as such, our energy use was 50% less than 2016 (1478 kWh). I did turn the boiler on for the basement heat, but not on the main level.

November: Solar generated = 234 kWh vs. Energy Use = 1569 kWh

  • It snowed on November 1st and stayed snowy and cold until the last week of the month when it got above freezing and melted a lot of the snow off.

December: Solar generated = 291 kWh vs. Energy Use = 2229 kWh

  • December was extremely cold again with several days of -40°F. Good fun. But still used way less energy then 2016 (almost 600 kWh less!) despite it being a similar month weather-wise.

ACTUAL TOTALS:

Actual Solar PV Generated = 8212 kWh (Comparison 2016 = 8189 kWh)

Actual Household Energy Consumed = 15,011 kWh (Comparison 2016 = 19,000 kWh)

Actual Total Energy Used (consumption – PV) = 6799 kWh (Comparison 2016 = 10,811 kWh)

Shheeeet! That’s good! I was pleased about 2016, but 2017 was awesome. That’s a 4012 kWh reduction of our electrical energy use from the previous year. And at $0.12/kWh that works out to a $481 saving for the year.

Granted we burned more wood this year than last. I’d estimate we burned around 3/4 cord of wood in 2017 compared to about 1/3-1/2 cord in 2016. But at $250 per 1 cord that’s still a good savings. My February experiment had the biggest single month change with mostly burning wood. I have no idea how to factor in the equivalent energy. Obviously it’s not zero. Maybe another post if I find some information on it.

Even so, almost every month we improved from the prior year. I think part of that was us getting used to the functioning of the house and getting our house thermostat temperatures dialled in better at least in the winter. As for why it was still less energy use in the summer months, well, I’m not sure?

Our solar generation was almost identical to the 2016 which was good to see.

My favourite comparison though is to the Canadian home average of 30,555 kWh/year. At 15,011 kWh, our house used 50% as much energy, while factoring in solar use, it’s at 78% less energy use then the average house. High fives!

Also we were again, way under the predictions of both the HOT2000 (19,328 kWh/year) and the PHPP (22,868 kWh/year), which is pretty sweet. Again, I have to wonder how close we would have come to meeting the Passive House standards had we made sure to reach the 0.60 ACH airtightness benchmark…

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Speaking of airtightness, in January (2018) we made a few changes to our doors to try and get a better seal.

I wrote in the “everything is perfect” article how we’d had issues with bowing of two of our three doors from Duxton. I’ve been really happy with the service of Duxton and they’ve been out to our house a few times now to tweak and make some changes to help optimize our house’s performance this past year. But the doors had been a problem since the beginning with not getting a great seal on top and bottom corners. In an apparent airtight house, leaky doors is not something you want. Due to the bowing of the door frames, Duxton offered to replace the doors at no charge. Still, we had some issues with getting a really tight seal even after replacement.

Duxton now offers multi-point locking doors which, like it sounds, have multiple latches that create an extra tight closure. Unfortunately, I didn’t know they were available at the time or they actually weren’t available yet when we ordered our original doors, either way a deadbolt with one single 1″ contact in the middle of 6.5′ tall door, inherently doesn’t create an optimal closure. So what were our options? We did chat with Duxton briefly about pulling out the doors and retrofitting them with their multi-point doors, but the labour and extent of work to do so was going to be terribly extensive. Instead, we went with a simpler option: cam locks.

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We had them install two of these low profile cam locks on each of the doors: one at the top and one at the bottom. Immediately we’ve noticed a difference. The house felt… snugger. We’ve also noticed a significant improvement in the heat retention of the house overnight. It does not cool off nearly as quickly at night, even on the -40°F/C nights. It’s tempting to have another blower door test done as I’m certain there has been a fairly dramatic improvement with this simple fix. I wonder how much under 0.72 ACH we’d be now…

It’ll be interesting to compare the above numbers with 2018. I’m not expecting as dramatic a change from this past year as I’m not going to burn as much wood – just what is comfortable for us. But I think the change in airtightness will have really positive effect. We will see.

The February Experiment: Heating with Wood Fire

Posted on by kent

After writing my last post, and happily confirming that our house had exceeded our expectations for energy use for 2016, I’d made the comment: “Based on the predicted numbers, the heating energy likely accounts for about 50% of our overall energy use. Makes me wonder too how much better we could do if we burned wood a bit more often?”

I’d written that without thinking about what that would mean too much. But after re-reading my post I got thinking, ‘Hmm… what if we did burn wood more?’

We tended to keep the thermostat around 70°F in the winter, which was comfortable, but would still allow us to have a wood fire on occasion and warm the house up to 73-74°F. It’s not that we really needed it, we just liked it. The in-floor hydronic heat can certainly meet our heating requirements. But we’d figured the wood stove would always be our back-up heat in the event of a prolonged power outage or in extremely cold weather. BUT – what if we flipped it and tried a little experiment? Make the wood stove our primary heat source and our in-floor heat the back-up. I’d also received our most recent bill from the power company which advised that our electrical rates had gone up 3% for 2017…so…

Impressively, my wife was game for the idea too. So, on February 1st, we turned the boiler way down, to 65°F, and started loading the wood stove.

My objectives for the month were:

  1. To determine if we would love/hate or be impartial to the need to fill the wood stove in the morning and night.
  2. To determine if we would be comfortable with the house temperature we could maintain.
  3. To determine how much electrical energy we could save by using wood as our primary heat source.

First off, I love our wood burning stove from Morso Denmark. And I love fire. Who doesn’t really? Isn’t their something primordial about sitting around a crackling fire with friends and family? We’d had it a mandatory requirement from day one of the house planning that we would have a wood burning stove in the main living space.

fire2

I’d only ever seen one house with the stove in front of the windows and I think it is a brilliant spot. It doesn’t obstruct our view during the day, but at night the fire gives a nice focal point to the room. This placement also allows it to be viewed from the kitchen, dining room and living room and extend it’s heat range to the bedrooms on the main floor.

We have a wood nook directly opposite the wood stove that is 24″x84″x20″ which contains the mess and also adds another interesting feature to the room.

living1

But enough about design and aesthetics (although I do want to write about that again sometime), let’s talk about function.

My goal was to keep the house around 69°-72°F during the day and a bit cooler at night while we slept.

The month of February was an interesting temperature mix. The first week was stupid cold (-30 to -40°F/C). But then typical for SK, it warmed up to above freezing temperatures for mid-month and then dropped to seasonal temperatures for the last week (-15°C or 5°F). This made it actually a very convenient month to test the wood heat giving us a fair bit of variety.

The first week (very cold week) we burned through the entire wood storage nook. This was surprising to me as I’d only filled it twice the entire winter beforehand! We were going to use up some wood. Basically what I would do is start a fire when I got up (it was good reason to get up and not to hit the snooze button too). The house temperature was around 66°F or 68°F most mornings. I’d get it hot, then load it up and turn the damper down before work. Passive solar gain would keep the house reasonably warm during the day and when we’d get home the house was usually about 69°F. We’d start the fire again and keep it burning until we went to bed, usually trying to get the house temperature up to around 74°F. Again, I’d load up the stove and turn the damper way down before tucking in.

I actually didn’t find this nearly as much work as I thought I would. In fact, I liked it quite a lot. Certainly it’s more work then just getting up and doing nothing, but it really wasn’t bad.

By the second and third weeks, we were in our groove, and the outside temperature was mild. We used half as much wood and the house stayed above 70°F most days and nights, which was higher then we’d had the boiler set at before.

In the last week, we used a bit more wood again, but it didn’t seem like much work. I ended up loading the wood nook three times for the month in total.

We had pine, tamarack, maple and poplar wood that we burned for the month. The pine and tamarack had been what we’d mostly been using for the winter. It’s a soft wood, but has high BTU output, so it burns hot, and also burns quickly. It’s good for a quick warm-up if the house is cooler, but it doesn’t give that prolonged slow burn you might want at night time. It does however burn clean, not giving off a lot of smoke and ash. Maple is a bit better for the prolonged evening slow burn given that it is a hardwood. While the poplar, well, it’s crap. I regret burning it. It’s a dirty wood, very smoky and lots of ash. It’s BTU output is crap too. Oh well. Now I know.

wood

OK so for objectives #1 and #2, I realized that I was generally impartial to the work of loading the stove. We loved the wood heat though. It was comforting and, in fact, most days the house was able to stay above the typical 70°F temperature we’d had the boiler set at previously, which was a nice bonus. Some of the really cold days when you’d wake up to 66°F inside were a bit uncomfortable for the first few minutes until the wood stove got things warmed up. Also, I didn’t really want to be in bare feet on the concrete floors. Even though the house would be warm, we generally would wear slippers.

Now, the big question was, was the extra time/effort worth the energy savings?

This was something that I was most interested in and there was no way to know for sure until I checked out power at month’s end. I’d had the data from 2016 so it was easy to compare the numbers. Based on my notes from February 2016, it was a similar month in terms of average temperature, however as you will see, there are some significant differences. I’m fairly confident that a direct comparison from February 2016 to February 2017 is reasonable. So what did the numbers show? Let me tell you:

February 2016: Solar generated = 553 kWh vs. Overall Energy Use = 2706 kWh

February 2017: Solar generated = 378 kWh vs. Overall Energy Use = 1258 kWh

First off, I was shocked at the overall energy use! It was a massive drop from the previous year. That’s a 64% drop in electrical energy! Wow. I  really did not expect that. And as you can see it’s not like we had an especially sunny month by any means, the solar generation was actually one-third less than last year so we weren’t even getting much passive solar heating.

Needless to say, I was very pleased with these results. When I crunched the numbers a bit more, the cost savings were $177.00 (1448 kWh x $0.12224/kWh)! In a single month. That’s awesome.

Roughly taken over the course of an entire winter that could be upwards of $1000/year in energy savings if we burned wood regularly. And now, well, I’m seriously considering doing just that…

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How Were Our Energy Predictions? An Analysis of the First Year Energy Use: Solar and Energy Performance

Posted on by kent

bwhouse

We had spent a lot of time planning and designing a house that would be energy efficient, aesthetically pleasing, and cost effective. This is a fine balance to try to find. However, it really is a big guessing game until you actually live in the space and track it’s performance. You can run all of the computer programs you want, but you really don’t know how things will be until you’re in and living your normal life.

We had installed PV solar panels on the house to combat some of our energy use with the hope that someday we could work towards a Net Zero home, but this too, seemed to be a big guess as to how well it would perform.

In the planning and designing stages of the house we ran a couple different energy models on the house. The first is called the “HOT2000” program. “HOT2000 is an energy simulation and design tool for low-rise residential buildings.  This software is widely used across Canada to support program, policy and regulatory development and implementation.  HOT2000 is developed and managed by the Office of Energy Efficiency at Natural Resources Canada” (NRCAN). It was originally designed for use with the R2000 energy efficiency program, which was an early promoter of green home building in Canada.

We later used the Passive House Planning Package (PHPP), which is now the widely used software program for building highly efficient homes worldwide.

My intent with this article is to report the varying predictions of the these two programs, as well as our predicted solar generation, and also to show our actual energy use for the year of 2016 – our first full year in the new house. I’ll also report some considerations and possible options for the future.

1: PRE-BUILD ENERGY MODELLING

I had been very curious about this when we were in the early stages of planning the house. Most of what I read was the predictions of various homes, but I’d only come across one house that actually tracked and reported its energy use – that being the Mill Creek Net Zero House in Edmonton, AB, Canada. Which, although using exceptionally little energy, did not meet it’s net zero target. That being said, it was very close.

I fully did not expect our home to be anywhere close to net zero, but we hoped that over the next number of years we could gradually build our solar panel array (as costs come down) to eventually reach our goal.

OK, let’s get to the numbers:

HOT2000 Predictions:

Annual Space Heating Energy Consumption: 7159 kWh

Annual Domestic Hot Water (DHW) Energy Consumption: 3409 kWh

Annual Appliance Energy Consumption: 8760 kWh

TOTAL = 19,328 kWh/year

PHPP Predictions:

Annual Space Heating Energy Consumption: 7584 kWh

Annual DHW Energy Consumption: 3974 kWh

Annual Appliance Energy Consumption: 11,310 kWh

TOTAL = 22,868 kWh/year

PV Array Predictions (6.2 KW)

PHPP Estimation: 7321 kWh/year

Solar Installer’s Estimation: 9300 kWh/year

So obviously there are discrepancies between the HOT2000 and the PHPP. Although their prediction of Heating and DHW are quite close, surprisingly the Appliance use was significantly different. Also, surprising was the discrepancy in the solar predictions – I was a bit disconcerted by the drastic difference of 2000 kWh/year!!

For comparison’s sake, according to Stats Canada website’s most recent 2011 home energy use data, a Saskatchewan home consumes an average of 30,555 kWh/year (110 GJ), of which electricity for appliance use is 8889 kWh/year (32 GJ).

Drum roll please.

… Actually first, some clarifications. All I have is our actual overall energy use. I cannot separate out Heating vs. DHW vs. Appliances unfortunately, although this would be interesting. The following information is taken from the solar panel’s generation and the Electrical meter. I tracked each month and have recorded it below.

OK, now the drum roll.

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2. ACTUAL ENERGY CONSUMPTION AND PV GENERATION:

January: Solar generated = 315 kWh vs. Energy Use = 3323 kWh

  • Yikes! I was a pretty worried when I saw this. That being said, January was very cold and has very short, dark days (-20° to -30°Celsius most days. We kept the house around 71°F).

February: Solar generated = 553 kWh vs. Energy Use = 2706 kWh

  • February is always a cold month. Although you can see the solar was getting a bit more sunlight already as the days lengthened.

March: Solar generated = 603 kWh vs. Energy Use = 1716 kWh

  • This was getting a bit better still. I lowered the house temperature to 69°F. It was getting warmer outside and more solar gain.

April: Solar generated = 979 kWh vs. Energy Use = 1385 kWh

  • April was warm and sunny. Nice spring weather. Started to not need the in-floor heat on at all during the day, but still ran it during the night.

May: Solar generated = 960 kWh vs. Energy Use = 1029 kWh

  • Almost net zero for the month. It was a very nice month. We were running our river pump frequently to water new grass, which I think increased energy use quite a lot.

June: Solar generated = 1434 kWh vs. Energy Use = 989 kWh

  • Net Positive in a big way. Beautiful month. Obviously the longest days of the year.

July: Solar generated = 956 kWh vs. Energy Use = 511 kWh

  • The first two weeks of July were cloudy and rainy which is unusual for July.

August: Solar generated = 950 kWh vs. Energy Use = 645 kWh

  • This month was very rainy as well, which again, isnot normal. Usually August is very hot.

September: Solar generated = 778 kWh vs. Energy Use = 611 kWh

  • Cool and cloudy. I replanted grass seed and was running the river pump a lot again.

October: Solar generated = 315 kWh vs. Energy Use = 1478 kWh

  • October sucked!! 315 kWh is the same as January! It snowed on October 4th. We had to turn the heat back on. There were only 2-3 sunny days all month.

November: Solar generated = 390 kWh vs. Energy Use = 1750 kWh

  • Cloudy month, but had some mild days mid-month with above freezing temperatures. Still, we generated more solar in November then October, which should not happen.

December: Solar generated = 229 kWh vs. Energy Use = 2857 kWh

  • Shortest days of the year and extremely cold (-40°F). What do you expect?

ACTUAL TOTALS:

Actual Solar PV Generated = 8189 kWh

Actual Household Energy Consumed = 19,000 kWh

Actual Total Energy Used (consumption – PV) = 10,811 kWh

3. DISCUSSION

I’m extremely pleased with these numbers! I’ve been waiting for two and a half years to know what our actual energy use would be.

We actually used less overall energy then was predicted by both the HOT2000 (19,328 kWh/year, although it was close) and a LOT less then PHPP (22,868 kWh/year), which is surprising that it was so off… It makes me wonder how close we would be to meeting the Passive House standard given the actual energy use is 3868 kWh less then it predicted… Hmm. Maybe we should have tried to hit that airtightness target of 0.6 ACH after all. Oh well.

Nonetheless, the overall energy use of 19,000 kWh is very good (and such a nice round number too!). We did not do anything different in terms of our behaviour except to just be smart and not be wasteful. I still baked bread every weekend and we used our larger appliances just like we normally would. We have two refrigerators and two deep freezers in the house. All the lights are LEDs. We try to hang our clothes to dry. We used our wood stove occasionally, maybe 2-3 times per week, but mostly just for ambiance and occasionally on the extremely cold days. That being said, based on the predicted numbers, the heating energy likely accounts for about 50% of our overall energy use. Makes me wonder too how much better we could do if we burned wood a bit more often?

As for the actual solar PV generation (8189 kWh), it pretty well split the difference between the installer’s predicted 9300 kWh/year and the PHPP prediction of 7321 kWh/year. I think this past year was on the cloudier side for sure. We had a lot of rain in the Spring and even more in the Fall, which is very unusual. Followed by an extremely early snowfall which seriously cut into our PV generation (see October – brutal). It probably would be closer to the installer’s prediction on a typical year (will have to see what 2017 brings).

Still based on the actual numbers, our solar panels did cover nearly 45% of our overall energy use for 2016. We would however need to double our solar panels (add another 6.2 KW array) to meet Net Zero with consistency year to year. Who knows, maybe in the coming years the costs will drop more and perhaps government incentives will increase. One can hope.

Comparing our house to the average Saskatchewan home consumption of 30,555 kWh, we did very well. Using 37% less energy then the average home. And when you take into account the solar energy generated that drops us further to using 65% less energy then the average house! Sweetness.

Considering that we are completely on electric energy, it makes sense to make the house as energy efficient as possible. The cost of electricity for us is $0.12224/kWh (while cost for natural gas power is about $0.04/kWh equivalent), which works out to an electricity bill of $1321.54/year (10,811 kWh x 0.12224). We do however have to pay a basic service fee of $32.61/month (even when we are net positive in a month) which sucks and then 5% tax. That brings our absolute costs for the year to $1798.50/year or $149.88/month, which is about half the cost of our previous homes power and electricity bill. I’m ok with that.

throughthetrees

This post was updated on March 4, 2017. 

Musings on Passive House Standards and the Costs of New Home Construction, Part 1

Posted on by kent

A friend of mine sent me this article for Tree Hugger yesterday about an Irish county that made the Passive House standard for all new home construction. This is a pretty big deal. The question then came up – why doesn’t Canada (or the USA) adopt such strict and stringent standards to their new home construction? Certainly the Paris Climate Conference of 2015 has finally made it official what everyone and their dog already knew: the world is overheating and we need to do something about it before we all die. Building better homes could make a massive difference in our world’s energy use. It is well-known that a certified Passive House uses 80-90% less energy than a standard house.

The problem, as usual though, in making such rigorous standards mandatory is a combination of bureaucracy, status quo, and resistance to change. In this post and my next, I will make the argument that I believe there is a skewed perspective on both sides of this battle in Canada.

Did you know that the minimum standard for wall construction in Saskatchewan (a province that has frigid winters of -40° temperatures for long stretches and over 10,000 heating degree days per year) is a 2×6 wall with batt insulation? The effective R-value of this wall is only R17.5 due to thermal bridging (as the wood studs bridge between the inside and outside of the wall). This standard must be out of date, you say? In fact, this was recently upgraded to this absurdly pathetic level in 2012 (it was only a 2×4 wall before that). Shameful.

As if this wasn’t bad enough, most homes in Saskatchewan feature R12 in basement walls and only R40 in the attic. There is no requirement for insulation under the slab of the house. Also, the building code requires only double-pane windows – such insufficient windows account for a massive amount of heat loss of up to 50% (these are usually vinyl framed windows, though sometimes wood or aluminum). And placement of these crappy windows can lead to further issues with heat loss due to inadequate southern exposure and large windows on the north side of house. Furthermore, air leakage rates in most new homes is about 2.0 ACH@50pascals (which is actually one of the lowest values tested in Canada). (Source: Energy Standards by Ken Cooper)

I assume that you can get the picture that our homes are generally very inefficient (don’t think that this is specific to Saskatchewan – this is relatively consistent across North America).

Although we did not build a Passive House, we followed the principles of this as closely as we could financially justify (which is the rub, more on this in my next post). For a quick comparison, our house has R56 walls, R80 attic, R32 basement walls and under-slab. Our latest air tightness test was 0.72 ACH@50pascals (and with some extra tightening we’re hoping to get this to 0.65 or less at the next test). We used triple-pane fibreglass windows. The design of the house maximized heat gain through the south windows and minimized heat loss through the windows on the east, west and north sides. Passive shading with our roof overhangs prevents overheating in the summer. The positioning of the house is directly south (a luxury we have living on an acreage). We also installed PV panels to offset our meagre energy use, which are becoming more and more affordable.

Now, a lot of people wonder and ask (I know I did prior to building), that it must cost substantially more money to build a house to this level of efficiency?

The simple truth is that it does not have to.

The general consensus is that a new custom home in Canada, excluding the cost of purchasing land, is between $200 and $300 per square foot to build (a contractor spec “cookie cutter” home built to the minimum standard with minimal features and cheap finishing can be $175/sq.ft or less). Indeed this is large range – for a 1500sq.ft home you could either spend $300,000 or $450,000. But for argument’s sake, let’s say $250/sq.ft is a realistic cost of a new custom home (we will also assume that most people would not build to the bare minimum construction standard of a spec house and see the benefit of adding triple pane windows and a 2″ layer of EPS foam on the outside of their 2×6 wall).

OK so where are the extra costs?

I would say that the design planning and orientation of the house will be the single biggest factor in determining your initial and long-term costs in a high performance, energy efficient house. It does not cost anymore to build a house with your windows facing north instead of facing south. Positioning the long side of your house to east does not cost anymore than facing it south. Designing correct overhangs for shading does not cost anymore than designing insufficient overhangs. Designing outcroppings, bay windows, and cantilevers does not cost anymore to design than a rectangle or a square-shaped building. Placing operable windows appropriately for cross-ventilation does not cost anything extra either. But all of these decisions and factors can have huge ramifications on the cost of construction and/or long-term costs of operation. We had several team meetings during our design process (including a Passive House certified designer, contractor, and LEED engineers) to decide on which systems would be best suited to be optimally energy efficient, be comfortable to live in, and also to make sure everyone, including sub-contractors were on the same page. This extra consulting time accounted for 2.5% of our overall cost.

In terms of actual construction costs, we built a double 2×4 stud wall that is 16″ wide. The cost of materials for this wall system versus the cost of 2x6s and the 2″ of EPS foam is almost negligible. Framing labour costs were slightly more though as each exterior wall was built twice (accounting for an additional 2% of the overall budget). Remember though our design is simple, a rectangle, meaning four walls – no bays or outcroppings. We also invested 20% more in purchasing fibreglass framed triple-pane windows versus the usual vinyl or wood triple-pane windows (accounting for an additional 1.75% of the overall budget). Insulation costs slightly more but pays for itself in short order when compared to long-term operation costs (the upfront cost is an additional 2% of the overall budget). Airtightness of the house did not cost us anymore than the standard vapour barrier (although it does require some attention to detail by the tradespeople) with the exception that we needed to install a heat-recovery ventilator which cost $1200 (0.3% of the budget).

But there are also some possible cost savings to consider. One can get away with a smaller mechanical heating system due to the lower heat load required in a super-insulated and airtight house. For us, our mechanical system cost about the same as a standard house due to us deciding to install in-floor heating and a wood burning stove. Although you certainly could get away with baseboard heaters or a very small forced air furnace combined with a heat coil on your HRV if you so chose (for us we wanted the in-floor heat and a wood stove – you can read about our reasons for this here and here). Most new houses also have air conditioners installed. We do not (cross-ventilation, insulation and proper shading is all that is needed).

The bottom line is that it cost us about 8% more to build a house that is in the range of 75-80% more efficient then a standard new custom home.

After these extra costs are accounted for the rest of construction costs are basically the same as any other house – how much do you want to spend to finish the house is based on your taste and how much you want to invest in your bathroom fixtures, lighting, hardwood flooring, custom cabinets (vs. Ikea), appliances and so on. Also, how much sweat equity do you want to do yourself? All of this will have a big impact on your end costs (consider, painting our house took 5 full days, but saved us about $6,000+. Installing the tile in the bathrooms and kitchen ourselves took 10+ full days, but saved us another $8,000).

Ok, so you’re probably thinking, how much did this damn house actually cost you? Tell me already! Although I haven’t done our final-final tally yet, it is in the range of $280/sq.ft. But this also includes the cost of our 6.2 kW solar PV system, our septic system, and the cost of trades to travel the 30 minutes to our house each day. Removing these factors, to build the same house in an urban area, you could easily do it for $250/sq.ft.

Say… that’s pretty much the same as what we said a typical new house would cost, right?

So why the heck isn’t everyone doing this??

Well, it goes back to the fact that there is an unfounded assumption that building an energy efficient house costs a lot more (I think we’ve shown that it simply does not have to). It also does not help that energy costs from non-renewables such as coal-fired electricity and natural gas are very cheap still (even so, those extra 8% in building costs for us should be paid back in less than 12 years in monthly energy bill savings). And the public outcry for action is not yet greater than the apathy of maintaining the status quo on the part of our government, the building industry, and those contractors who have been making a tidy profit on their suburban sprawl spec houses.

Part two to come…

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