I'm looking at building the builders cottage within approx 2 yrs. Have been purchasing fixtures/ect as sales and opportunities present themselves. What I'm looking at buying at the moment is the heating system for the house. My thoughts are either electric baseboard, or direct vent propane heater. Planning on a wood stove too, but need something to provide heat when not at home. I like the direct vent propane over the electric, just due to the fact that I wouldn't be dependant on the electric grid for heat. I can purchase an 18,000 btu housewarmer for $299. On sale through the 22nd, otherwise $399. My main question is will this be considered an appropriate heat source when the inspector/code enforcer comes through? I'm in eastern wi, and cannot find anything on the counties code website that says this wouldn't be allowed, but am just wondering if anyone has had experience in using this type of heater as a primary heat source. Thanks much!!
How long away when you are not there?
This can make a difference.
For example: Insulate the home with a min of R21 walls and perhaps give it an R38 floor and roof. Then install small wood stove (Vermont Aspen is what I have as do others) and it will warm the place up nicely. When you leave damp it all the way down and let it smolder...
come home 8-10 hours later (from work presumably) and it will still be warm. Clean out the ash, relight the stove and you'll be warm all night :)
if you want the "away-time" heat to be very long, for example for the full work week, assuming you will be visiting only on weekends, then you need only minimal heat during that time, i.e. only to prevent freezing. that's not so expensive as installing a full-blown house heating system.
so in addition to the gas heater - a must for heat while you are there but sleeping, or if you feel too lazy to work the wood stove - i'd install a mimimal amount of electric heat - for example one baseboard in bathroom, and one near kitchen - both controlled by separate 220V direct-control wall thermostats.
it's not clear that a gas heater can be set low enuf to just prevent freezing. more likely the lowest setting will heat more than you really need, and thus cost more than you want in gas consumption. also the mechanism (fiddly gas control valve) is probably not as reliable as electric heat. and the pilot might blow out. but if you do use the gas as your away-time heater, the additional electric heat setup acts as last resort backup in case the gas runs out. of course electric could go out too...
you can also use the bathroom one to warm it up before taking a shower. electric heat is very reliable and inexpensive for the materials (but not the electric consumption.)
Thanks for the quick replies guys....This house would be for full time living. Not just on weekends. The plan would be to use the woodstove when there, and propane or electric to keep the house in the mid 60's while at work. Insulation-wise the plan is to go with r21 walls and at least r 30 in the ceiling. My main concern is that having the direct vent heater wouldn't pass the inspection, or be up to code. If that would be the case I'm thinking of doing electric baseboards throughout the house. So that's my main question at this point-in your experience would a single direct vent heater be up to code as the primary heat source, as most likely the wood stove would be seen as a secondary source. I'm just looking at any way to avoid having to do a forced air system and the associated expense. In addition I can't find anything in a forced air system that wouldn't be oversized. Right now i've got a 80+ year old 675 square foot house with a rheem 2 stage that's something like 32,000 btu on low fire and that heats the space just fine. I'd imagine something that size in a small place like the builder's cottage would be too much...especially with modern insulation and construction techniques.
According to a little chart I have WI would require 50 - 55 BTU per sq ft. That's a ball park figure and does not take into account the many variables. Going by that though it would seem the 18000 BTU wall heater should suffice.
As to the question of would a direct vent wall heater be accepted? I don't see why not. But I could be wrong.
We have a Housewarmer 18K unit in our cabin. The pilot has never gone out on it's own. We use it as the backup heater, but I am confident that it could handle the entire heating load for us. That is a guess though. We have R18 in the walls, R25 floor and R45 ceiling, 16x30 no loft, quality low-e windows.
The only way to know if that heater would satisfy your local inspector would be to ask him/them.
Our place is in NE Wisconsin, and the only heat source when we purchased our place was a woodstove. The cabin is about 12 years old, so assuming there was an inspection, there was no issue at that time. Also, outside wood boilers are very popular, and inspectors don't seem to mind those. When we go away, we use portable electric radiator style heaters that are on a digital outlet thermostat. The outlet thermostat is infinitely more accurate than the one built into the heater itself, and is programmable. We have two of these, on separate circuits to prevent a complete shutdown due to a blown breaker.
When we built our addition, we had pex tubing installed in our slab, as well as insulation underneath the slab. I built a simple in floor heat system using a 15gal water heater, circulation pump, and a few other parts. If we leave the doors to the addition open, it helps heat the rest of the cabin, so the portable heaters don't have to work as hard. The in-floor heat is nice because other than a thermostat on a wall, and a small utility closet, you don't know the heating system is there, unless you are barefoot that is. An on demand water heater would also work well in this application, shrinking the use of space further.
Here is the thing, with the level of insulation you are planning, banking the woodstove with some good hardwood before work should easily keep you in the 60's all day. We have 2x4 walls(less insulation) and stay above 60 all night without adding wood.
All of Wisconsin's building codes are hosted online at: http://dsps.wi.gov/sb/SB-DivCodesListing.html. The residential codes are called the Uniform Dwelling Code. If I remember right, in the northern part of Wisconsin there was a requirement for minimum R49 in the ceilings and R21. Double check the code to make sure.
Our building inspector doesn't have a problem with our sole source of heat as being a woodstove. His only requirement was that we install some ceiling fans to move the heat around.
Also double check building codes for the town that you are building in. We ran into some suprises when we found out that the town of Wagner had more strict codes than the state.
I am building in Central NY and a direct vent propane heater was perfectly code compliant for me. I purchase mine ahead of time for $150 on craigslist. The inspector just had to check the documentation that the vent was the required distance from any windows.
IIRC, there was a code requirement for an automatic heating system. Ventless propane is against code for this requirement in most jurisdictions. Electric is code compliant too, it was just cost prohibitive for me to connect to the grid. Propane also gave me the option of being code compliant for the lowest cost. A good wood stove and chimney runs into the thousands of dollars, while propane is only a few hundred.
With any code requirements set aside you might considering some problems with an outside boiler furnace.
These require regular maintenance with cleaning the tubes (heat exchanges between the firebox and the boiler tank. They have to be fired almost twice daily. If you live in a colder climate they cannot be allowed to go without heat or they will freeze. So intermitent use is out. They require a large amount of wood to operate in a heating season. This is dependent upon the particular size stove but on average you can look at 8-12 PU truck loads of wood.
On the upside they can be used as hot water heat or forced air heat(air exchanger). Most can be adapted to serve several purposes. Forced air heat, hot water baseboard, domestic hot water and even pool or hot tub heat (size dependent). If a constant supply of wood is available and you are going to be living there full time then it might be a viable alternative. It also requires power. Depending on your off grid/grid arraignment they need to operated with a circulator pump and fan draft.