We are getting ready to do a major overhaul to about half of our house. We currently heat with an old wood furnace tied to an oil furnace setup. The house originally had no insulation and this setup struggled to keep the house at 65 on cold days here in Maine. We burned cloe to a cord or wood a week when it was really cold.
I air sealed and insulated the attic to R50 and insulated the rim joist and top 4' of the basement a couple of years ago. Now it is a challenge to keep the fire low enough to not over heat the house. The walls are still empty.
The house is a 1400 ft2 ranch. I plan to gut about half of it this spring. I will be replacing the windows with something decent, but not top of the line. I plan to put 3" (R20) of closed cell spray foam in the walls and then 1" of rigid foam on the inside to minimize thermal bridging. There is currently a fireplace with an insert in the living room which I plan to remove. Also I can shut off 2 rooms at the end of the house during real cold weather to reduce the area to 1100 ft2.
Now to my actual question. I plan heat the house with a single direct vent propane heater. I haven't done any load calcs yet, but probably need a unit that produces around 40000 btu/hr. Does anyone have any suggestions as to what model to install?
There will also be a small wood stove in the basement for supplemental heat when necessary.
Hey Al, the Rinnai ES38-P looks like a winner. All the reviews seem quite thoroughly positive, and the company seems a solid one. Best of luck not overheating, especially if you're going to R-28 walls where you now have zilch. Maybe you'd be better off with a smaller unit - maybe even just an inefficient FRIDGE would heat your house!
I am leaning toward a Rinnai. The literature says that the ES38-P has a modulating gas valve with 8 settings and a multi speed fan. This should let it adjust to the load as it changes. I am not sure how much the efficiency is impacted when running at the lower settings.
I will get a smaller unit if the numbers look like it will do the job. Minus 20F is not uncommon here most winters. This year has been a exception.
Do the loads first, have some one do a room by room load, that will give you the total load but will also give you airflow to each room needed for comfort. A 1400 sq ft house, airflow to far rooms will be a larger problem than the amount of heat. Look at a Variable Speed fan that can run constant fan at low speeds and low electric costs.
I am a TRANE dealer and really like the equipment. There are cheaper systems out there but no one has a lower failure rate. As in most things it isnt the brand but but the quality of the installer that determines your experiance with any heating system
Thanks for the response. The floor plan will be very open when I am done. Just the common living/kitchen area, 1 bedroom and a bath room that I want to keep warm. The two other rooms at the far end of the house can be cooler and not cause a problem.
Be careful with an oil to propane conversion. You may actually end up paying more with propane. Remember there is approx. 140,000 btu's in a gal of oil, and 93,000 in a gal of propane. Figure it out for both oil and propane then decide.