Most sesible heating system for a new house build on Vancouver Island
We are in the planning stage for new construction of a 2 level 2600 sqft home on Vancouver Island. As we’re in the process of allocating budget we would like to know what the most sensible heating system to use will be. We require electricity to be our primary source with wood heat as back up, as we lack natural gas and propane is too expensive. We understand that base board electric is the most cost effective for install, but we’re looking to improve efficiency, durability and sustainability with increasing energy costs in mind. As far as we know our options are as follows:
-Air to air heat pump
-Air to water heat pump with hydronic heating and domestic hot water
All the above considered, we’re attempting to build for $150-$200/ sf and would like to be realistic with our budget and sensible pay back for a sustainable heating system.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
At $150-200/s.f. you should be able to build a Net Zero Energy house (PV included!), heated by ductless mini-splits.
Carter Scott is able to hit the $200/ft^2 price point n a much colder climate than Vancouver Island, without substantially more insolation.
Air-to-water systems would cost more than double that of ductless air-air, with no appreciable difference in efficiency, but a very modest improvement in comfort (especially f you like to hang around in your socks indoors in winter.)
Getting the individual room loads for doored-off rooms way down is key to comfort when considering point-source heating like wood stoves or mini-splits, but it's a lot easier to get there in locations with outside design temps of -8C or higher (covers most of Vancouver Island) than it is at -20C (typical for many of of Carter Scott's Net Zero house locations.)
Dana, I wonder about PV here on the Island. We get almost no sun during the heating season. Perhaps that isn't as important as it feels living here?
The last two houses I did have wood stoves and electric radiant heaters (at your recommendation- thanks!). If the wood heat wasn't going to be used I'd probably spec a mini split, but either way still include the radiant cove heaters so as to be able to zone the house.
There is a great deal of information on ductless minisplits on the GBA site. Enter "ductless minisplit" in the GBA search box and you will be reading for hours.
The better your home's thermal envelope -- in other words, the more airtight the envelope, the better the insulation, and the better the windows -- the easier your house will be to heat.
It usually makes sense to spend a little more on your thermal envelope, so that you can spend less on heating equipment.
You wrote, "I wonder about PV here on the Island. We get almost no sun during the heating season."
If we are talking about a grid-connected PV system that is installed in a location where the local utility offers net-metering contracts, it doesn't really matter whether the sun shines during the winter. If the utility gives credit for excess PV power produced during the summer, you can still end up with a net-zero-energy house -- even if the winter months are dark and cloudy.
I put that poorly. My question to Dana, or anyone else, is whether given our low electrical rates, mild climate and lack of sunshine it currently makes sense to install PV here on the Island.
Just from looking around I suspect it doesn't, as we have always had a fair number of innovative, low energy builders here in BC and I don't see them including it in their projects.
This december BC is introducing a new energy code which will make our residential housing a lot more efficient. These types of code changes make it a lot easier to convince clients to spend on efficiency upgrades. When the base is raised, it isn't as hard to suggest adding that bit more.
For those interested here is the new code: http://bccodes.ca/BCBC_9%2036%20EnergyEfficiency.pdf
Using wood heat as your main heat source is key. In a well built house the new EPA wood stoves are perfect. Have back up electric baseboards, but nothing fancy. Wood heat is carbon neutral, provides warmth that mini splits do not provide and cost of ownership is extremely low compared to other solutions. The better built (air tight and insulated) will not require as fancy HVAC system so take advantage of that! Use the money saved on a wood stove towards other things and enjoy. You can also tie in water heating for further savings and efficiency.
"The better built (air tight and insulated) will not require as fancy HVAC system "
Until now houses here on the coast were only required to have bathroom exhausts linked to a dehumidistat, but the new code changes mean full time mechanical supply and exhaust, regardless of the type of heat source.
If that is code now, ouch. I hope they have a prescriptive plan that can be used in lue. Code can be a blessing and a curse. Think more implementation of the older codes consistantly would be a better deal for everyone.
The new EPA wood stove standards this next year could have been done better. The one thing that needed addressed really wasn't. They needed all fireplaces to be EPA inserts. Open fireplaces are one of the weekest links in modern homes. The new regulations are exactly like air sealing a wall while leaving the windows and doors open. A good thing to do, but lacking common sense.
That's the problem with regulation verses education. Education is always the answer, both to the consumer and to the builder. If the government inspectors are better educated then codes will be enforced and persprictive plans implemented when codes fail. I've fixed code violations after being inspected before. That is a bad situation, considering another trade would have covered up those code violations thinking everything was done right.
Hopefully the new regulations give common sense flexibility in your area to the inspectors.
If going all electric I've mentioned HTHP units in lue of mini splits. If a costly HRV w/back up heat is required with a mini split then a HTHP is looking like a better solution more so. There is no reason why the inverter tech in mini splits will not be used in the HTHP is future models. Wood heat is still a better option for above reasons.
Good point. I do a lot of work for a nearby resort where half the cabins have wood stoves and half open fireplaces. The frequent winter power outages provide a good chance to compare the two as the log structures lose heat very quickly. The ones with stoves are of course fine, but the ones with open hearths are better off not to start a fire at all as the amount radiant heat thrown off is dwarfed by the losses up the chimney.
I guess as long as open fireplaces are seen by the occupants as something akin to a TV, rather than a heat source, not much harm is done?
lol, if considered a tv, no harm, right.... I know that's the arguement for not epa'ing the open fireplaces. If open fire places where actually like a tv, then the fake electric fireplaces would be considered premium then in stead of a open fireplace? It's just for looks right? A little tongue in cheeck with the pro open fireplace people. The fact is a home owner likes both the look of the fire and the heat aspect. Without the heat from the wood, people don't consider it a bonus.
If the fireplace is akin to a appliance like a mini split or a HTHP then it needs regulated like one. No? Sort of funny that the EPA has about regulated Diesel Fuel from cars - which contains around 30% more energy than normal gas. Then they look at open fire places and don't say a word.
S.E.: I'm not sure I understand your comment about the EPA and diesel cars. There are plenty of diesel fueled cars available in the US.
Lot of the diesel vehicles made in Europe are illegal to be sold in the US. Because of the EPA. And now urine has to be added to the exhaust as well. Just strange since diesel is a more efficient fuel but their is so many regulations stopping their sales in the US. Then the open fireplaces which pollute way more they don't regulate at all.
To be clear, I wasn't necessarily recommending installing solar PV as part of the initial build, only pointing out that at your budgetary numbers you actually COULD hit Net Zero with air source heat pumps & PV.
In any new construction it's prudent to design the roof pitches & orienation to be able to take advantage of PV later though. The rate at which the installed cost of PV is falling is still quite high, and even if it doesn't pencil-out as a financial win in super-cheap electricity locations today, it almost certainly will at some point in the next 15 years. The long term "learning rate" trend for the past 3-4 decades has shown than very time the installed base of PV doubles, the price drops by about 22%, and the doubling rate has shrunk to less than 2 years. Over the most recent 5 years that learning rate has increased to something north of 30%, but even if it drops back to the long term rate it is destined to become the cheapest form of energy (any type) by 2030. If doubling rates shrink or learning rates stay high (both could happen) it could be true well before 2025.
Spending the money on the highest-efficiency building envelope to the degree that point-source heating (whether wood stoves or mini-splits) is the right approach, which opens up the heating "system" options, increases comfort, and should be possible well within your stated budget. In your climate even PTHPs can run at reasonable efficiency, but if you're willing to spend for comfort, mini-splits are much quieter, higher efficiency and will keep room temps more stable. In a cheap-electricity market the case for higher-efficiency mini-splits diminish, but in expensive markets the case is still pretty easy to make (especially in places with much lower wintertime temperature avearages than yours.)
But all starts with the heat load calculations.