Supplemental heating for independent zones

[John]

This is a rather big one, and I'm hoping I'll get a bit of discussion going on this, as there's lots of angles to this, and I frankly am curious to know what other people have come up with.

I have several rooms/zones in the house, which can be somewhat independent from other areas in the house as far as heating goes, and I'm wondering what my options are. I was thinking, for example, if I knew I was going to be in the basement all day, I could turn down the main furnace to say 68, and then use a supplementary heater to bring just the basement up to 72.

I should add, that my basement tends to be colder than the rest of the house, so to get my basement to 72, I would have to crank the regular thermostat to 75 or so (which I would never do), so I would need a supplementary heater in the basement one way or another.

What I'm looking for is a comfortable solution, that is somewhat energy efficient. I have a high-efficiency gas furnace right now, but I'm thinking adding electrical space heaters might actually reduce my heating costs if I used them correctly.

Also, I don't want this to be a pain to manage. That is, I don't want to have to walk around the whole house and adjust the vents/ temperature guages each time I switch rooms. So, what I need for that would be some integrated smart controllers... (Am I going to far here?). OK, while I'm dreaming, heating/cooling the zones based on time of day, and days of the week would be nice...

I'm curious to hear what other people think / know about this

John

[RBM]

The first thing you might want to try, is having the forced air system balanced, so all the living spaces are heated evenly. If there were separate zones on the existing system, you could find a way to control them however you like, but that not being the case, you'll need to add supplemental heat to areas that you want warmer than others. Electric heat is 100% efficient, so dragging a portable unit to the basement or wherever, is not a bad solution. If you're always in the basement or wherever, every Tuesday from X to Y, you can use an appliance timer to control the heater

[ransley]

I have forced air and do similar, so I cut in a 3 big vents on my

600sq ft basement that I open only when i want heat. I also open an additional return. Its all sealable so it works. Heat rises, , cutting off the basement only saved me 15% with a R20 basement wall and im Zone 5, to - 20f. So the comfort lost may not be worth the cost if the basement is insulated and sealed. Or else use a wood stove or electric heater in the basement. a wood stove would do it well

[DerbyDad03]

re: "Electric heat is 100% efficient, so dragging a portable unit to the basement or wherever, is not a bad solution. "

I've heard that hundreds of times but there is still a part that confuses me.

Like many other houses, my basement is cooler than the rest of the house and I occasionally will use an oil-filled radiator to warm the space up if I need to spend time down there. I also use a small space heater with a fan to warm up my basement shop.

I know that the heaters are "100% efficient" but all that tells me is that all of the electricity is being used to create heat. What is doesn't tell me is how much it's actually costing me to heat the space with an electric heater as compared to adding more forced air ducts.

Sometimes when I read that line, it almost appears to be saying "Electric heat is 100% efficient so go ahead and use as many electric heaters as you want, wherever you want, for as long as you want."

That can't be the case, right? If it was, we'd all just turn off our forced air furnaces and go all electric. Since in most areas electricity is more expensive than NG, why *isn't* it a bad idea to use an electric heater as supplemental heat?

I've always had trouble getting my head around that one. Must be I'm missing the "understanding electric heat" gene.

[trader4]

If you want it automated and have good access to the ducts involved, you could consider installing a system with automatic zone dampers. It won't be cheap though. And even with that, unless you go to motion detectors, it isn't going to follow you around and automatically adjust.

Other alternative is to use electric heater or heaters in the areas you will be using. How much it saves and whether it's worth it, obviously depends on a host of factors and is something you need to figure out.

[Ralph Mowery]

Yes, the electric heat is 100% efficiant, but it usually cost more than many other kinds of heat. You may have to say that a heat pump is 200% efficiant and gas and oil is 150 % efficiant compaired to the electric heat. What you really need to know is how much each BTU is going to cost with each type.

[ransley]

.

Electric is usualy about double the cost per BTU, or the that heat you get. There are electric furnaces and boilers made, but nobody buys them because the cost of electricity is to high and always will be since electricity is a byproduct of other fuels. It costs to convert gas to electricity.

[ransley]

Electric costs me near double per BTU of gas, Zone Dampers for humidity? you usualy have great ideas, but I have found humidity migrates very well , dont forget zone dampers will pull electricity

24x7 on the controll unit and at the cost have a long payback.

[RBM]

Exactly, the fact is, there is no waste on the user end. But it's rarely the cheapest way to go. I kind of liken it to my utility company asking me if I'm willing to pay more per KWH if they buy into windmills

[Ed Pawlowski]

? "DerbyDad03" wrote

You have to compare on Btu for accuracy. A gallon of fuel oil is 138,700 Btu. At 85% efficiency 117,895 will reach the heated space. That means you need 34kW of electricity for the same heat. Today, oil is about $3 a gallon and in my area, electric would cost $6.20 for the same amount of heat. 1kW = 3412 Btu.

You can do some rough comparisons with different fuel here

When you see those expensive electric heaters on sale, you are getting screwed on initial cost as well as the potential savings. I can heat a big portion of my house for the same as a single room with a space heater. I'm also glad I replace my old boiler two years ago as the savings are even greater with the high oil costs.

[trader4]

The key here is "supplemental". Even though electric heat is the most expensive, if you just use one electric heater to warm one room that you are going to be in for a long time, while turning down the heat in the rest of the house, you can save money.

Also, there are different types of electric heaters. If you're going to be sitting at a desk for 8 hours, you could use a radiant electric heater. Instead of heating the whole room, it heats mostly you and the immediate area arround you, via radiant energy. That saves by not heating the whole room, further reducing the energy used. If you use a radiant heater like that, turn down the heat in the rest of the house to 60, I'd bet you would come out ahead, especially in a large house that is poorly insulated.

It's the above factors that lead to the misleading marketing from shysters selling way over priced "miracle" heaters, that drastically reduce your energy consumption. What they are claiming is true to a point, but the real savings come from the above, not some new technology miracle from China....

[DerbyDad03]

OK, so let's toss this in:

Let's say I run an electric oil filled heater to keep my basement a bit more comfortable, but don't turn the main thermostat down. At first blush, we'd assume it's costing me more, right?

How do we factor in the heat that rises and both warms the sub-floor (there'd be *some* radiant heat into the first floor, wouldn't there?) and also enters the first floor through the kitchen door?

How do we factor in the fact that the basement air is now warmer and when it gets sucked into the furnace around the filter slot, it won't reduce the temperature of the air in the return as much?

While I'm sure it wouldn't completely offset the cost of running the heater, it has to bring it down some, right?

Finally, my furnace uses the basement air for the combustion air. Does the warmer air help or hinder the combustion process?

[Ed Pawlowski]

? "DerbyDad03" wrote

Still going to cost more. As the heat rises, the thermostat is going to be satisfied and not call for heat so you continue to use the more expensive electric heat. Sure, the basement is more comfortable, but at a cost.

Hot air going into combustion is slightly more efficient than cold air going it. I forget the number, but you can gain a few percent with enough of a temperature rise of combustion air but all that warmed air you are burning is being replaced by infiltration of cold air in the house anyway. To increase the efficiency, duct in fresh air for combustion and do not use the circulated heated air at all. That is the way all high efficiency burners work today. Required by code in some places.

The only way electric heat saves money is to greatly reduce the amount of heated needed in unused rooms. If you use the examples I used yesterday, for every Btu of electric I'd use, I'd have to reduce the oil heat use by twice that just to break even. I tried it one month and it was a costly experiment.

There are things you can do to improve efficiency, but there is no changing the laws of physics. You want heat, you pay for it one way or another.

[trader4]

I can't see any way that it would not cost more. First, you're heating an additional space with electric. Second, even if all the heat made it's way to the rest of the house, you're generating that heat with electric, not your main fuel, which was oil or gas, right? Given the relative costs of those fuels, and even allowing for 100% eff of electric and say 80% for gas/oil, it's still almost always expensive to generate the same amount of heat with electric.

Sure, you get some benefit from some of the heat from the basement electric heater making it's way to the rest of the house. But I would bet that it's not a very large percentage of the heat.

If that's happening, I'd seal up those duct leaks. But yes, under current assumptions, that heat too is getting transfered to the rest of the house.

Yes, but I wouldn't bet on it being much.

I don't think it has any effect at all on the combustion process. But using air at say 70F instead of 60F means you do get a wee little bit more heat out of the furnace, so yes it helps too.

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[trader4]

I think you misread something along the way. I suggested zone dampers to adjust temperatures in various area, not humidity. I agree, that for humidity zoning isn't going to work.