Gas fireplace/stove as main heat source
The house we are currently in is about 1100 square feet, fairly well insulated, and has electric baseboard heat. We are in Montana, but the mildest winter part of the state. We have only ever used the baseboard in the living/dining room, and the floor plan is open enough that it heats the rest of the house. We turn the heat off completely at night (when the thermostat reads around 70, usually) and it’s right around 58-60 in the morning. In other words, the house is not too hard to heat.
However, we are pretty sick of paying $220/month for electric. Would a gas fireplace or stove be anywhere close in efficiency to something like a Rinnai wall unit? From the specs I can tell, many gas fireplace/stove units are a little over 80% efficient, and the Rinnai ones are 84% efficient. How accurate are these numbers? Will a gas stove/fireplace with a thermostat really be as equally efficient?
Replies
jesse,
there is no easy answer to your question..
gas rates vary a lot, electric rates do as well. efficency of the unit is only one part of the question.
What about when the unit isn't working? a fireplace requires intake air and exhaust air, those are open 24/7/365. basically it's like leaving a window cracked open all year around..
It may have a 84% rating and might actually achieve near that.. but what about the times when it's not on? Are those glass doors a good seal?
Consider a package heat pump.
You need to do a comparison that factors in the cost of electricity vs the cost and efficiency of gas. Where I am, electricity is fairly cheap and propane is very expensive, so gas is not the most economical heat source, especially when it's running an 82% appliance. It gets better if you're running a 95% mod con boiler.
It's fairly easy to find the conversion factors online and put together a comparison. A cubic foot of gas contains a certain number of BTUs... but I forget the exact numbers... and you can likewise convert a kilowatt to BTUs for comparison purposes.
A cubic foot of natural gas is about 1000 btu's and if I remember correctly a kilowat of hydro is about 3500 btu's.
That's a definite maybe.
Hydro is 100% efficient.
roger
Hydro... is that the energy produced by burning B.C. Bud?
I have a spreadsheet somewhere with the conversion... you plug in the cost of a kilowatt and a gallon of propane.
Did you make plans to get down to the JLC show?
96283.6 in reply to 96283.5
Hydro... is that the energy produced by burning B.C. Bud?
If you are burning that stuff you won't care about the price of hydro or for that matter what hydro is.
I'll know wednesday morning I hope.
roger
As a general rule, it's more efficient to heat with gas than electric. Yet, there are still things you can do to increase your comfort.
Baseboard heat is notoriously inefficient. Reason for this include poor air circulation, low humidity, and little thermal mass.
The first thing to address is humidity. Not only does moisture help transfer heat - it also makes you fell more comfortable. Placing a large pot of water in an oven set to 'warm' ... or a tea kettle on a low simmer ... makes a noticeable difference.
There are very few homes that cannot be helped with a few fans. "Vornado" type fans move a lot of air, with little noise or turbulence. Your best bet is to place them so that they blow air across the heating elements, or out of 'dead spots.' Heat trapped at a 10 ft ceiling does you no good at all.
Finally, the issue of thermal mass. In short, you're better off heating 100 pounds 10 degrees, then 10 pounds 100 degrees. This is one reason that so many wood stoves have water tanks on them. Ordinary electric baseboard heat has little thermal mass.
There are two ways to supplement your baseboards with more efficient electric heat.
The first is to use those portable heaters that look like radiators. Paint them flat black. Set up a fan to blow air over the fins. These radiators are much more efficient than the usual electric baseboards.
The second is less obvious, but remarkably effective: get a waterbed!
Finally, there is one place that really needs to have a warm floor: the bathroom! For that, I suggest a heat lamp, mounted in the ceiling. It's about the only time I recommend that sort of 'radiant' heat!
general rule, it's more efficient to heat with gas than electric. Yet, there are still things you can do to increase your comfort.
Baseboard heat is notoriously inefficient. Reason for this include poor air circulation, low humidity, and little thermal mass.
With electric heat it is 100% efficient in that you get all the BTU's that you paid for. Most if not all of the burner type heaters all have chimneys and therefor lose heat and efficiency. Unless you have a really tight damper on the chimney you lose heat even when the unit is off.
I'm talking about efficiency not cost or whether a person likes one type of heat over another. What you say about electric heat helps but most of that would help with any type of heat (humidity).
Cost in local areas make the difference of which type to heat with. About 20 years ago I replaced my old faulty oil furnace with electric baseboard heat because hydro was cheap but within a few years the cost went sky high so I put in a new high efficient gas furnace.
I live on the west coast where heat pump work really well but I wouldn't put one in ( and I can do all that work myself) because of the cost to install (even with me doing it at wholesale price) plus maintenance and repairs later on. The cost to operate it would be really cheap but if you do a cost analysis over 10-15 years it isn't cheap for the ordinary person to own.
Right now I have an electric furnace and to save money I wear sweaters and the wife is going back to putting heavy drapes on all our windows.
roger
I'll have to disagree here ... though I can't claim that I understand all the nuances. Every listing I've seen of efficiencies has placed electric heating ... whether it be resistive (the cherry red coiled wires in the air) or baseboard square at the bottom of the pile. I am given to understand that the inefficiency is in two major areas. First, a fair amount of the energy is released as light (though some of that may not be in the visible spectrum). Secondly, it takes a lot of energy to maintain the element at that higher operating temperature. I suppose you might compare it to the 'more than double' drag on your car when you 'double' the speed. Which, of course, brings us back to another comment of mine: paint the radiators flat black. This makes them more efficient at radiating the heat they contain. Were you to take two identical radiators, paint one black and one white .... you'd find a significant temperature difference on the surface of the radiator - even though the two were drawing the same current.
The black one would be 10-25 degrees cooler. Since the two are putting out the same 'watts', the black one can be cooler only because it is transferring more heat to the air around it. It is more efficient.
Interesting points. When I was in HVAC we figured, if I remember correctly, 3500btu's of heat per 1000 watts (1Kilowatt). That 3500BTU's was used on any type of electric heat regardless of whether it was radiant or convection heat. I have to agree that getting the heat from the element to where you want it or feel it quickly enough varies and some are better than others.
Maybe there are other ways of figuring out efficiency that I'm not aware of. Years ago I was in the coal business and certain types of coal had certain BTU values per pound. In fact pretty well everything has a BTU value per pound. You can burn something really fast with lots of BTU,s per hour or slow with minimun BTU per hour. A piece of newspaper will give a flash of BTU's in a fire but won't last very long whereas a candle will last a long time with little heat. You can't have both usually. I've actually forgot where I was going with this. Oh well:)
roger
You're quite right about perception being half the battle. When I had hot water radiant heat in my cement slab, the place felt quite toasty with the thermostat set at 65. I attribute this to the fact that it kept your feet warm .... and, laws of physics notwithstanding, it was actually warmer at 'sofa level' than at 'thermostat level.' When I was visiting Finland in the 80's, many places had these absolutely massive stone 'fire places.' With but a tiny hole in which to burn a small log, that was plenty to cook breakfast .... and heat the home for the rest of the day. As you might guess, the cabins were laid out around these stoves, and even had a sleeping platform on the back side. I was given to understand that .... forgive me if I mangle this ... not only was the wood burned- so was the smoke. Then virtually all of the heat released was trapped in the stonework, for gradual release during the day. One thing is certain: that log burned up fast, and there was very little ash. A log in the morning, a log in the evening, and you were set. I know, it's hard to believe, in a land where reindeer are 'pets.' :D Still, it is important that the heat be where it is needed, rather than wasted on heating the entire place. For example, look at the chilly offices where the secretaries have tiny heaters under the desks. That little 'bubble' of warmth under the desk makes a real difference in their comfort. If you can't have a heated floor .... well, let's just say I was simply amazed at the difference a second layer of carpet made on my perceived comfort.After all, who ever thinks to insulate their floor? In a similar manner, this year I can already notice the difference 1" of foam makes. That is, the foam panel I attached to my supposedly insulated steel door. That steel door was one heck of a draft maker.
Personally, it sounds like a good place to start is maxing out your insulation and sealing air leaks where ever possible. Regardless of how much insulation you put in a house, it's almost the only investment that pays for itself over time.
Beer was created so carpenters wouldn't rule the world.
I know nothing about BTU's, efficiency or costs etc. But I do have a gas fireplace in our family room. It's self-contained, fresh air from the outside and vented to the outside. The front is glass, no doors. Oh, and a fan to distribute the warmth.
However....... it gets SO darned hot that we never use it! Even for ambience at it's lowest setting it get TOO darned hot in the room. And the room is in an "open" floor plan house.
Don't know if it's "efficient" .... but it does throw out the heat!!!!
I don't know if the gas fireplaces and stoves are regulated by the Department of Energy and have the standard yellow energy efficiency stickers or not. If they do, they should have an Annual Fuel Use Efficiency or AFUE which is designed to take into account the losses when the appliance is off.
The standard wood burning fireplace is very inefficient. It is possible that if a wood burning fireplace is used to supplement a heating system that it will actually let more heated air go up the chimney then it radiates into the room.
If the gas fireplace has its own air intake and exhaust like another poster indicated that his does, and it does not depend on the wide open chimney flue, it is likely that it can be reasonably close to the stated efficiency. It would be my guess that it would be cheaper to heat with the gas fireplace if it has an 80% plus AFUE than your current electric heat. How much I cannot tell you.
Like others have indicated, many things can affect comfort and whether a gas stove or fireplace will be as even or as easy to control, I do not know.
You might consider a pellet stove. We heat out 3600 sf house with one, and it works well.