Compact space heating equipment
In the (hopefully) near future I will be jacking up my 800SF bungalow to gain some extra square footage for 2 bedrooms, a small bathroom, and a rec room. I was working on the floor plan last night, and currently I am heating with and oil fired furnace (forced hot air), in the plan I am quickly realizing that I really do not have a whole lot of room for a bulky furnace, nor do I want to sacrifice headroom for ducting. My thought was to convert to a gas fired boiler and put baseboards or rads in the upper floor, and radiant slab in the basement. I also heat with a wood stove as much as I can which I will likely be moving into the rec room since that is where a lot of time would be spent.
Is a gas fired boiler (propane) a smart decision? I picked this because my oil tank is due to be replaced in the spring so this would be an opportune time to make the decision to make a switch, and I certainly do not want to go electric ($0.13KWh). I am in NS, Canada. Climate zone 6a I believe?
Insulation levels in the house are not amazing, but they are about as good as they will get (without MAJOR renvation) as it is a very shallow scissor truss in most parts of the house (R32 batts I believe?) and a small section is a regular truss which I will be blowing in cellulose to about R30, as well as keeping the existing fibreglass batts. The walls are 2×4 with fiber glass, and 1″ EPS on the outside I believe… The basement will most likely be ICF walls w/2×3 inside stud wall for electrical or any plumbing, and sub slab will be 3-4″ high density EPS.
Any insight would be greatly appreciated.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Mark Pennell,
For an overview of heating equipment options, check out the relevant articles in the GBA Encyclopedia:
https://www.greenbuildingadvisor.com/green-basics/green-heating-options
https://www.greenbuildingadvisor.com/green-basics/heat-distribution
You might also want to read Heating a Tight, Well-Insulated House.
Propane is almost always a significantly more expensive fuel than oil. It generally costs more per gallon, and provides significantly fewer BTUs per gallon -- a double whammy that hits you in the wallet.
The more money and effort you are willing to invest in air sealing, insulation improvements, and window improvements, the less you'll have to worry about heating.
A good quality modulating condensing boiler (at 95% efficiency) may not cost you any more for fuel than an older 75%-80% efficient oil furnace, and it burns much cleaner so does not require the annual cleaning and tuneup that an oil burner does. It can also provide unlimited hot water with an indirect tank.
However, a quality boiler, water tank and radiant heating system is going to be a major investment. It may make more sense to invest the money in better windows.
If your house is small, well-insulated and well-sealed then it may make more sense to install a direct-vent Rinai wall heater in each floor unless lots of partitions and closed doors make heat distribution problematic. But, if your woodstove heats the house, then a propane space heater should as well.
If you can afford it, there's nothing nicer than radiant heat. But don't expect it to pay off in energy cost savings so much as in comfort.