what will be the best solution for heating and cooling?

**bb873** · 03-13-2013, 07:01 AM

Hello,

We are leaving in the Montreal area. We just bought a house built in 1956 in which we are going to have a complete reconstruction. Only the outside wall and roof will be kept, all the inside walls and windows will be removed to build an entirely new inside. All the space will be well insulated. The house is 1700 square-foot, 850 per floor - a main floor and a basement.
• In the basement we will have a family room, 2 bedrooms, a bathroom and a technical room for the furnace.
• In the main floor, we will have an open space with the kitchen, a dining room and a saloon, a master bedroom and a bathroom.
We plan to have a gas stove (Jotul FireLight GF370DV) in the main floor that will be running 2-3 hours a day on winter evenings

My question is – what will be the best solution for heating and cooling?

Thanks for your help

**Dana** · 03-13-2013, 07:54 AM

All good heating system designs starts with room-by-room heat load calculations at realistic indoor and outdoor temperatures, then adding them up to find a whole-house value. The 99% outside design temperature for Montreal area is between -24C/-11F and -22C/-7F. Most people use something between +20C/68F to +22C/72F for the indoor design temperature in making those calculations.

"Well insulated" is a meaningless description from a heating & cooling design point of view. The exact construction type, insulation type, and R values are necessary for making the heat load calculations, as well as the U-factors & sizes of the windows & doors. Include the foundation type & insulation too.

Also, what are your fuel options? (Natural gas, propane, oil, electricity, wood, wood pellets?)

Without the heating & cooling load information, there's no telling what a "best" solution would be. It's rather like asking, " I live in Montreal, and will have a skateboard in my car- what is the best car for my situation?" The answer to the car question will depend on what else needs to go in the car, how fast/slow it needs to go, and what sort of minimum fuel economy it needs to get.

So, let's start with estimating the heat load- how is it built, and what are your R-values/U-factors?

**bb873** · 03-13-2013, 08:57 AM

I appreciate your sense of humor. I don't know what will be the insulation rating. Since the inside of the house will be entirely rebuilt it will be compliant with Québec regulations. Windows and doors will be energy star. The fuel options are - natural gas or electricity.
We were considering having a gas furnace and a heat pump. But it requires additional baseboards in the basement. Having 2 zones seems too expensive. So, is a gas furnace still pertinent? Instead, shall we install baseboards in the main floor and do not consider having a gas furnace anymore? What about mini-split heat-pump. Would it be a less expensive solution to install 2 mini-split units in the main floor and baseboards in the basement?

Thanks again

**Dana** · 03-13-2013, 03:20 PM

At current code-minimum R values & U-factors in Canada, heating with mini-splits in your area might be a bit difficult, but not impossible. As long as you have the Jotul to back it up you won't necessarily suffer, but it makes getting to the real heat load numbers correct even more critical.

Only the Mitsubishi "Hyper Heating" units have a rated output at -25C, which is approximately your outside design temperature, and it will stop running completely when it gets down to about -28C, which does happen from time to time in Montreal. (It will automatically re-start when it warms up to -25C though.) Most vendors output ratings end at -20C. They will continue to run at lower temperatures, but the output is "unknown", and you need to know at what point they automatically turn off.

When heating with mini-splits, keep in mind that rooms with doors that can be closed off from the area heated by the mini-split need special attention, and may need very high performance windows to keep from getting too cold when the doors are closed for extended periods.

I'm not sure what current code minimums are for R values in Montreal. I understand that R50 attics are now required everywhere in Ontario. The best I could come up with in a quick search is this document. If you can tell me how deep the insulation is and the type, and the stud spacings it's possible to come up with a reasonable estimate on heat losse are per square foot or per square meter, and we can work on it from there.