Now that it's winter, thought I'd try something with a room space heater that I've been thinking about. Much savings can be gained, I'm told, if one keeps the thermostat low for the house heat while using a space heater in an occupied room.
The oil filled space heaters don't seem to me to be that efficient. What I am thinking of is to take one, carefully abrade/scrape off the paint taking extreme care not to puncture, and using heat conductive glue attach a large aluminum sheet such as roof flashing to the "coils". This should increase the area the heat radiates from at least 10 times. And since I'm not fussing with the electrical parts of the unit at all, there should be no safety issues. I might add a small fan and cowling as I progress.
I'm just basically giving the unit's heat a more efficient path to interface with the room's air. If this works I would hope to not use the unit above the low or medium setting.
This is an extremely crude pic of what I'm thinking.
The oil filled space heaters don't seem to me to be that efficient. What I am thinking of is to take one, carefully abrade/scrape off the paint taking extreme care not to puncture, and using heat conductive glue attach a large aluminum sheet such as roof flashing to the "coils". This should increase the area the heat radiates from at least 10 times. And since I'm not fussing with the electrical parts of the unit at all, there should be no safety issues. I might add a small fan and cowling as I progress.
I'm just basically giving the unit's heat a more efficient path to interface with the room's air. If this works I would hope to not use the unit above the low or medium setting.
This is an extremely crude pic of what I'm thinking.
Attachments
The first question is what type of space heater to buy as the start. Not interested in radiant heat, which strikes me as dangerous. That leaves oil filled or water filled. The oil filled models are easy to find, but I wonder about their efficency. There are a small number of water filled models available apparently.
The oil filled models seem to use something called "diathermal" oil, which I imagine facilitates heat transfer. Intuitively, I would think that water filled would be better. Came across a chart, and I don't know if the "diathermal" oil is on there under another name, but oil does not appear to be as good for heat transfer as water.
http://www.engineeringpage.com/technology/thermal/transfer.html
Which means that oil filled space heater will not be as efficient putting out heat as a similarly equipped water filled heater.
Is this true? Before I commence this, I want to make sure it's worth the extra effort to secure a water filled unit.
Any advice I can get on this would be immensely appreciated.
The oil filled models seem to use something called "diathermal" oil, which I imagine facilitates heat transfer. Intuitively, I would think that water filled would be better. Came across a chart, and I don't know if the "diathermal" oil is on there under another name, but oil does not appear to be as good for heat transfer as water.
http://www.engineeringpage.com/technology/thermal/transfer.html
Which means that oil filled space heater will not be as efficient putting out heat as a similarly equipped water filled heater.
Is this true? Before I commence this, I want to make sure it's worth the extra effort to secure a water filled unit.
Any advice I can get on this would be immensely appreciated.
I'm not sure what you mean by a 'space heater'. If it is an electrical heater then you can be sure that whatever design it uses and whatever you do to it you will get almost exactly 100% efficiency. 1kW in = 1kW out. Anything else would violate energy conservation. I sometimes see adverts for 'efficient' electrical heaters. Either they are ignorant, or they are hoping their customers are ignorant.
Radiant heat, in moderation (as from a domestic heater), is not 'dangerous'.
Radiant heat, in moderation (as from a domestic heater), is not 'dangerous'.
I think you would be better just having individual thermostats for each radiator in a room and just turning up in the room you are in. The cost of electricity is much more than gas (I assume your main heating is gas).
Also, adding fins etc to a radiator does not increase its efficiency, all it does is change its surface temperature. The energy expelled into the room remains the same. And thermally conductive epoxy is expensive.
Also, adding fins etc to a radiator does not increase its efficiency, all it does is change its surface temperature. The energy expelled into the room remains the same. And thermally conductive epoxy is expensive.
As pointed out, all electric heaters are 100% efficient. The difference is in how efficiently they heat you. The most efficient system would be to wear electrically heated clothes, followed by a radiant heater aimed at you. To heat the whole room, the most efficient would be underfloor heating. The least efficient would probably be a convection or "space" heater, which usually results in a layer of stagnant hot air near the ceiling while your feet freeze. A fan heater, or a ceiling fan with a convection/space heater, would be better.
Alright, I knew that eventually someone would ask a question I can actually help with.
Peter, What they ^ have said is true in most points. The best you can do is to add a fan to the mix to help circulate the air better. If it's a small room, this might backfire as the moving air can give a cooling sensation so the fan must be on low.
Peter, What they ^ have said is true in most points. The best you can do is to add a fan to the mix to help circulate the air better. If it's a small room, this might backfire as the moving air can give a cooling sensation so the fan must be on low.
Convection heaters aren't too bad provided that the air inlet is near the floor and the room ceiling is not too high.
I once worked for a few years in an open plan 'office' which had been 'converted' from a repair workshop for domestic appliances. The ceiling was quite high, and the only heat was from convection heaters on the wall with their inputs at about waist height (when standing). We froze when sitting at our desks. We stood up to get a bit warmer.
I once worked for a few years in an open plan 'office' which had been 'converted' from a repair workshop for domestic appliances. The ceiling was quite high, and the only heat was from convection heaters on the wall with their inputs at about waist height (when standing). We froze when sitting at our desks. We stood up to get a bit warmer.
Thanks for the advice, guys. I just figured that since loudspeaker diaphragm area increases efficiency, and fins help a transistor's heat sink more efficently conduct heat away from the device, (and transfer it into the room), that fins would more efficiently transfer heat from the source, (space heater), into the room.
Guess not though. Good thing I checked with you guys first, saved me the effort of putting something together that won't work any better.
Rich: I use oil heat and it's costing me a ton. 200 gallons gets used a month and I only have a 3 bedroom ranch house with a full unheated basement underneath. In my case, I think the electric bill boost from keeping one or two occupied rooms warm with space heaters will cost less if I turn the oil heat for the house down several degrees
Speaking of which, I read that a heat pump can be 300% efficient. Anybody know how that works?
Guess not though. Good thing I checked with you guys first, saved me the effort of putting something together that won't work any better.
Rich: I use oil heat and it's costing me a ton. 200 gallons gets used a month and I only have a 3 bedroom ranch house with a full unheated basement underneath. In my case, I think the electric bill boost from keeping one or two occupied rooms warm with space heaters will cost less if I turn the oil heat for the house down several degrees
Speaking of which, I read that a heat pump can be 300% efficient. Anybody know how that works?
I've used the DeLonghi oil filled heaters for years and been very happy.
Now, from electric coil to heating the oil to heating the fins to heating the air takes some time. So these heaters are really for continuous heating or heat supplement-like what you are talking about, I think. They are not good at all for "I just came in from the cold and I'm freezing and I want to warm myself" nor are they good for "I'm gonna work in the garage for an hour and need some heat."
Not all types of "heat" are the same: some heaters like the oil type heat the air. Others make infrared (??) waves that directly heat your face/body. The above mentioned high ceiling office should have been using that.
And yeah, a slow fan would be good, but truly slow fans (Casablanca style) seem very hard to come by unfortunately. Maybe some very quiet PC-type fans might help a bit.
How about more insulation in your house? Not practical?
Now, from electric coil to heating the oil to heating the fins to heating the air takes some time. So these heaters are really for continuous heating or heat supplement-like what you are talking about, I think. They are not good at all for "I just came in from the cold and I'm freezing and I want to warm myself" nor are they good for "I'm gonna work in the garage for an hour and need some heat."
Not all types of "heat" are the same: some heaters like the oil type heat the air. Others make infrared (??) waves that directly heat your face/body. The above mentioned high ceiling office should have been using that.
And yeah, a slow fan would be good, but truly slow fans (Casablanca style) seem very hard to come by unfortunately. Maybe some very quiet PC-type fans might help a bit.
How about more insulation in your house? Not practical?
I think the house is fairly well insulated, it was built in 1970. Not new, but the windows, (Anderson crankout with removable storm) fit well. It's not like an older house where the wind blows right through the window sash. The oil company's technicians say things are working well, but considering the house has a full basement for insulation, has substantial solar heating in two large rooms via large windows that the sun shines through and the house is not really large, it's hard to figure the oil use.
My sister has a small house on the outskirts of much colder Chicago, with no basement to insulate the main floor, and she pays maybe $150 monthly for heating. I'm paying $700.
Maybe a Casablanca style fan for the space heater will be my next project.
My sister has a small house on the outskirts of much colder Chicago, with no basement to insulate the main floor, and she pays maybe $150 monthly for heating. I'm paying $700.
Maybe a Casablanca style fan for the space heater will be my next project.
Wow, 700 dollars per month. No wonder you are concerned. In the UK we are encouraged to fill wall cavities with insulation and our loft/attic are also lined with insulation over 1 foot thick. Do you have any such insulation? I don't think a basement will really help with keeping the heat in as heat rises mostly, and walls emit. My house was built in late 70s and the insulation had to be upgraded substantially, maybe yours does too?
By cheating. Most of the heat output comes from the environment (e.g. ground, or external air) so when 'efficiency' is expressed as (heat out)/(electrical power in) it looks very good.kelticwizard said:
Some electrical appliances emit energy in some form other than heat (e.g. light, sound). For these the heat is wasted (in the summer) so reduces efficiency. An electrical heater should produce only heat so is 100% efficient.
I know someone with an UNINSULATED brick house in Chicago; she pays about $300!
You are on the wrong track entirely, and I mean that in a kind way.
Something is WAY wrong in your situation-some big heat leak you are unaware of. You badly need an energy audit, especially someone to infrared-image your house for hot spots. The oil or gas or electric or whatever company may provide that free or cheap. If not, since you are spending so much per month, invest in hiring a professional.
head-unit is right, something is way off.
I have a 2 bedroom house and a double garage, house heated on natural gas and garage on electric, my bills only get to just over $300 in the coldest months.
And that is with -30 to -40F weather too.
You need to improve your insulation, in your walls, attic and your crawl space as well if unheated, especially on exterior crawl space walls.
The infrared imaging is a great idea, it can help pinpoint the largest heat loss areas, so you can concentrate on those first.
Insulation in a 70s house will be no where near what is spec'd out now.
I currently have 18" of pink in the attic, 4" of pink in the walls and rigid foam around the crawlspace perimeter, and that is not really good enough.
Plus the insulation you do have has to be installed properly, voids properly filled, not bunched up and not just stuffed in there.
Hiring a pro to give you some suggestions is not a bad idea, you are spending way too much money on heating costs.
The better you insulate your house, the warmer it will be in the winter and cooler in the summer, well worth doing.
I have a 2 bedroom house and a double garage, house heated on natural gas and garage on electric, my bills only get to just over $300 in the coldest months.
And that is with -30 to -40F weather too.
You need to improve your insulation, in your walls, attic and your crawl space as well if unheated, especially on exterior crawl space walls.
The infrared imaging is a great idea, it can help pinpoint the largest heat loss areas, so you can concentrate on those first.
Insulation in a 70s house will be no where near what is spec'd out now.
I currently have 18" of pink in the attic, 4" of pink in the walls and rigid foam around the crawlspace perimeter, and that is not really good enough.
Plus the insulation you do have has to be installed properly, voids properly filled, not bunched up and not just stuffed in there.
Hiring a pro to give you some suggestions is not a bad idea, you are spending way too much money on heating costs.
The better you insulate your house, the warmer it will be in the winter and cooler in the summer, well worth doing.
That's what we do. The place is kept at 17ºC and we have forced air electric for when it gets cold. The kitchen stays warm as we are always in there cookin' up sumpin.
Heat pumps are great. It's just an air conditioner in reverse. Expensive to purchase and install, especially the geothermal ones, but once you have swallowed the initial outlay, your heating, while not free, is really cheap.
Yikes.
I heat my house to 65 - I have a '50's ~1000 square foot 3BR rambler with a full basement and attached garage. I would guess my walls are R8-10 and in my attic I have perhaps R25. My windows are sliders (the leakiest kind, but I leave the storms on all year) and my bills (combined gas and electric) rarely exceed $200/mo in the coldest months in Minnesota. $700/mo is a lot, are you heating your house to 80F?
Those electric oil filled radiator heaters work quite well if you simply place a box fan or a noiseless fan a few feet behind it. Use the fan on low, and it will help to spread out the heat. A ceiling fan helps too. You may have to set the heater on it's lower setting because the heat transfer is faster with the moving air. Closing doors or draping curtains over the doors to rooms you are not using will make a difference. This way you can heat the house to 60, and have the living room at a warmer temperature.
Plug an extension cord into the external outlet of your neighbor's house during the night.......kidding of course
If the heat pump is not maintained properly or if it is filled too much with coolant, it will not work very well perhaps freezing up and run your bill sky high. If you have a heat pump and a $700 bill, perhaps a maintenance check is in order.......unless you are Al Gore trying to heat ONE of your mansions with all the carbon credit money you've funneled from the racket. Can't all be from your stock holdings in the Occidental Petroleum Corporation, Al.
Plug an extension cord into the external outlet of your neighbor's house during the night.....
..kidding of course If the heat pump is not maintained properly or if it is filled too much with coolant, it will not work very well perhaps freezing up and run your bill sky high. If you have a heat pump and a $700 bill, perhaps a maintenance check is in order.......unless you are Al Gore trying to heat ONE of your mansions with all the carbon credit money you've funneled from the racket. Can't all be from your stock holdings in the Occidental Petroleum Corporation, Al.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.