Hello:
We are building a retirement house, Spring 2013, north of Montreal, Quebec Canada. It will be a single story bungalow, 30' x 42', built on an 8” cement (crawl space) foundation over bedrock – clearance averages 4 feet.

I am 63 years old and my wife is 53 – she will not live in it after I am 'gone to that big construction site in the sky'. She will retire in about 5 years.

What I am trying to figure out is how much money should I spend on insulating the house?

Let's say that I am around until I'm 80, 17 years. We will be heating a 1260 sf house with electricity and an efficient wood burning fireplace for ambiance. Electricity costs around $0.075 per kWh or $0.000022 per Btu. The degree days here are about 6,500.

So, is there a way to work backward from ** the amount that we would like to pay for annual heating ** to the R-value of the insulation in the walls, ceiling and basement, to break-even in 17 years?

Thanks.

Rob-

Resistance electrical heating would be an expensive way to heat in the Montreal area. If that is your plan, using an air source heat pump (minisplit) should reduce energy consumption and pay for itself. I assume natural gas is not available, as that also would be a much less expensive way to heat than electrical resistance heat.

What are code minimums for insulation in your area?

Edited to add: In answer to your question, the computer model BEopt, a free download, is made to directly do cost tradeoffs for different levels of insulation, types of windows, types of HVAC equipment, etc. It takes a little patience to download and learn.

what is the expected rate of increase in electrical rates over that time? You'd need to know that.

If you have a well and a place to dispose of water, you might even find that geothermal pays for itself. A 4' crawlspace wouldn't be my choice.

If you don't want to do BEopt yourself, I'm sure there are consultants you can work with.

Thank you.
Lee Dodge
What are code minimums for insulation in your area?
1. Ceiling: R-30
2. Wall: R-20
3. Basement: R-10

I'll look into an air source heat pump (minisplit) - it looks like a good idea.

Bob I
what is the expected rate of increase in electrical rates over that time? You'd need to know that.
I'm not sure where I can get that information. I'll look...

jonr
If you have a well and a place to dispose of water, you might even find that geothermal pays for itself.
I did look into that and it would cost about $17,000 here. (Closed loop using my artesian well as a water source.)

A 4' crawlspace wouldn't be my choice.
Not mine either but the slope of the land, and the lack of a budget to blast, requires it – part of it will have 6 feet clearance, say 20%.

I'm saying that you can't figure payback if you don't know what your costs will be, but you can be assured they will be higher than they are now. you could look at the rate of increase over the last twenty years and use that figure. The Canadians at Building Science Corp in Boston recommend R values of 5/10/20/40/60 (windows/under slab/basement walls/walls/roof - in the Boston area, so plan on at least that. Also consider that in twenty years, especially with higher fuel costs, the resale value of a house with higher levels of insulation will be greater than one that costs more to heat. Also, with high insulation levels you can use heating systems which are less expensive to install and to use.

I'd check more geothermal providers for better prices and ask why they aren't quoting open loop. The differential between air source and water source isn't logical (the equipment is very similar and often priced about the same).

With a 4 to 6' crawlspace, I'd add a few feet and have a partially exposed basement that can be used for living space or a garage. Or forget the whole thing and use a frost protected shallow foundation (no need to go to bedrock if the soil is stable).

geothermal pays for itself....would cost about $17,000 here
Minispllits are also heat pumps like geothermal, and should cost 1/3 to 1/2 as much as your geo estimate. The capacity may be less, hence the need for higher levels of insulation, so you'll use less energy and have less ongoing cost.

Posted By Bob I on 12 Dec 2012 01:15 PM
I'm saying that you can't figure payback if you don't know what your costs will be, but you can be assured they will be higher than they are now. you could look at the rate of increase over the last twenty years and use that figure.

Good point. The whole "ROI" thing really oversimplifies a much more dynamic issue. Electric bills have risen dramatically in the last five years here in the States. I just received a letter in the mail stating my electricity rates will go up 5% next year. For instance, going from paying 11 cents per kWh to paying 25 cents per kWh like they do in Europe would totally change the whole ROI model. That $200 a month summer electric bill would jump to $500. People by nature will choose to "waste" resources if it is cheaper for them. If you tell someone it will cost $10,000 more to insulate the home more efficiently but it will take 25 years to pay back, 90% of consumers will pass on the better insulation to save $10k.

Just look at the whole SUV/Hummer 1990's/2000's craze. People were buying gas guzzling SUV's that got 10MPG because gas was cheap. GM, Ford and Chrysler had a hard time keeping up with demand on building big inefficient trucks and SUV's. When the gas prices rose, nobody wanted those SUV's. Sales plummeted on the Big 3 and people couldn't give their SUV's away. When it cost $35 to fill an 18 gallon tank, nobody cared, but when it cost $75 to fill that same tank, they all complained.

There are too many unknowns with utility costs. Heck, my water company increased their rates by 20% in one year. One should build a home within their budget and spending some extra $$ on energy efficient building practices has an overall better long term investment for the consumer and planet. The less energy the home has to use within its 50-100 year lifetime, the better.

Lbear,

Amen!

Another way I look at energy upgrades is to look at the fact that people do not pay cash for a home its the mortgage cost of that upgrade. example 10,000 energy upgrade is 45 dollars a month right now , the fact that rates are so low enables you to get the upgrade very inexpensively on monthly basis. An upgrade of this 45$ could be saving you 90$ monthly a 100 % monthly return on investment.. 100% 30 day return better than that granite counter top

Posted By Bob I on 12 Dec 2012 02:43 PM

geothermal pays for itself....would cost about $17,000 here
Minispllits are also heat pumps like geothermal, and should cost 1/3 to 1/2 as much as your geo estimate. The capacity may be less, hence the need for higher levels of insulation, so you'll use less energy and have less ongoing cost.

Sorry, I quoted bobi instead of jor.

The geothermal guy said that a closed-loop system would cost even more because I would need to drill a second artesian well. The actual quote was $13,000 for the equipment and about $4000 for duct work.

minisplits = no well, no ductwork; just a heat pump and condenser

Posted By Bob I on 12 Dec 2012 04:21 PM
minisplits = no well, no ductwork; just a heat pump and condenser

But it may be too cold for mini-splits to really work (with sufficient output)  at the 99% outside design temperature  or just slightly colder than that in robert.thompson's location north of Montreal.  At the average winter temp for Montreal it's going to be running at about half the efficiency of a so-so geothermal application.  Yes, the  Mitsubishi H2i series has a rated output at -25C, but the efficiency at that temp is barely better than electric baseboards.

In a super-insulated house backed up by a wood stove it may not matter- the geo would still never pay off unless electricity tripled in price (not too likely given the surplus capacity within HydroQuebec's operations.)  But in climate that cool mini-splits aren't the slam-dunk obvious solution that they are a few miles south of there.  Burlington VT averages about 5F warmer in January than Montreal, putting it on the steeper part of the efficiency derating curve for mini-spits, where that 5F really matters.

Rob-

You specified your code minimums for insulation. Bob mentioned the Building Science Corp. recommendations of 5/10/20/40/60 (windows/under slab/basement walls/walls/roof. Those two levels of insulation should define the range for consideration. I had a house similar to the one that you are describing built in 2010, and I ended up at 3/5/19/29/60 (windows/under crawl/crawl space walls/walls/roof. However, the R-3 windows become ~R-5 windows at night with cellular shades down. For a crawl space, I thought the R-10 underslab could be changed to R-5 under conditioned crawl space gravel. R-40 walls are what I would call "non-standard" and were not available to me in my (almost) standard production house. Even bumping the walls from R-19 to R-29 resulted in an increased cost with a predicted payback time of 42 years. You can see the payback times for all the insulation changes that I made at http://www.residentialenergylaboratory.com/costs.html. Your costs may be different.

I examined overall inflation compared to "energy" inflation for electricity and natural gas in Figs. 13, 14, and 15 at http://www.residentialenergylaboratory.com/comparison_of_pv_systems.html. The consumer price index inflation rate from 1913 - 2010 averaged 3.58%. Retail price of electricity in the U.S. from 1997 to 2009 inflated at an average of roughly 3.1%. The average residential cost of natural gas in Colorado inflated at a rate of about 4.7% between 1989 and 2010. (Natural gas costs have dropped since then due to the current market glut.) Federal regulations on natural gas distorted prices earlier than those times. I judged these inflation rates to be similar to the going mortgage rates, allowing me to do cost trade-offs using current costs without accounting for cost-of-money or inflation rates.

If you want to know the future inflation rates, see the lady with the crystal ball and/or tarot cards.

You can cherry-pick a decade here and there to invent an electricity price inflation above the general inflation, but the 30 year trend on electricity prices is still behind the general inflation, confounding the predictions of those railing against acid-rain remediation as "too expensive" and "economy crushing".

http://metricmash.com/344p

Even 1997-2009 isn't a particularly alarming period, with electricity lagging the general inflation for the first half, then leading for the second half, moderating sharply at the end:

http://metricmash.com/344q

Cheap natural gas and the rapid buildout of both high-efficiency combined cycle gas and wind-power are putting downward price pressure on US electricity pricing , despite the "wind is too expensive" naysayers who don't really analyze the long term contract pricing, or the effect of having more $0 bidder capacity on the day-ahead market. The marginal per-kwh cost of gas-fired power has a lower limit based on the fuel, whereas the marginal cost of wind power is effectively zero, which is ruining the business models of high-priced low capacity factor peak generators. The lifecycle cost of new-wind is continuing to fall in cost by 3-5% per year too- it's still an evolving/improving technology. (Wind has an economic rationale as decent slice of the generating portfolio, with or without a production credit subsidy. But it'll get built faster with the subsidy than without it.)

But regional differences in electricity prices and price-trends are huge. Hydro Quebec has a chronic surplus they would LOVE to sell to the US, were the regional US grid infrastructure heavy enough to handle it, and electricity prices in Quebec have low to no powerful upward price pressures. (That may change if proposed powerlines get built in New England over the next 20 years.) Electricity prices have been deflationary to flat in New England since 2008, somewhat counter to the nation as a whole. My own delivered per-kwh rate today is lower than in 2008, even without adjusting for currency inflation. It's definitely not keeping up with inflation looking at the 4 year trend. But it would be stupid to project that price deflation too deeply into future expectations.

Rob-

Something that I forgot to mention is to specify windows with high solar gain if you have reasonable solar exposure. In some parts of the U.S., you will get low solar gain windows unless you fight for the high solar gain coatings. Hopefully in Canada, they default to high solar gain windows. So you would like to have the solar heat gain coefficient (SHGC) greater than 0.45, meaning that 45% of the solar radiation can pass through the overall window area including the frame, etc. You should also consider a roof overhang of about 2 1/2 ft., at least on the south side, to block out the solar gain in the summer but allow it in the winter. The roof overhang will also reduce weathering of the paint, and reduce chances of water leakage.

On another subject, jonr did not like your crawl space with 4' clearance. I have a conditioned crawl space with 4' clearance, and find it a useful place to run the ductwork for my hot-air furnace, as well as the fresh water and waste water plumbing. I also use it for storage. Different strokes for different folks.

Thanks Lee, I read your website and posts with great interest!
The gable end of my house will be facing south but I was planning on a 2 foot overhand.
I was planning to use my crawl space for storage too. The 6 foot section may hold my electrical entrance (breaker box), water pressure tank and whatever.

I can insulate the crawl space walls but probably not the bedrock floor, well, at least not easily nor inexpensively. I will cover the bedrock with heavy VB

What should the crawl space wall R-value be if it is heated?

And, most importantly, should I insulate the floor over the crawl space? Do I VB it?

Thanks.

P.S Is there someway to turn this pain-in-the-ass bedrock problem into an asset by using it to store solar heat?

Rob-

The standard house plans for my house had a gable end facing south. However, I talked with the builder about making it a hip roof instead. Making it a hip roof solved two problems at once: (1) it provided an overhang to shade the high solar gain windows during the summer; and (2) it provided a roof surface with almost a perfect angle for mounting my solar thermal hot water collector. The 9/12 pitch roof results in a 36.9 deg. angle relative to horizontal, and the latitude is 38.5 deg., so essentially perfect. The builder liked the looks with the hip roof better, and made the next house in the subdivision with the same floor plan with a hip roof too.

I changed the garage roof from a hip roof to a gable roof and rotated 90 deg. to get a big flat surface at a good angle for mounting the solar PV panels.