Most efficient space heater?

[IamIan]

Originally Posted by eco_generator

Never even considered that an airconditioner is an efficient heat pump... wow. Will have to think about that one, I have a few extra window units sitting in my basement (the part that didn't get sprayed with poo water)

I've crudely used a window unit with a 12.0 SEER to pump heat into or out of a room ... and a continuation of that project to make it better and to properly quantify the results is one of many things on my project list ... eventually I'll get to it.

But I will give a few considerations to keep in mind if you also plan to tinker a bit with the idea yourself.

#1> Mass produced window units don't seal well in the window ... You don't want to reduce the insulation of a room , from the outside cold by a larger joule amount than any heat pump gains... there are a variety of options ... either to better seal the units ... or to put the units hot and cold sides in a box that vents the heat from point A to point B ... which ever direction you want.

#2> The hot side of the heat pump for even a small ~5,000 BTU window unit ... can get pretty hot ... so before you leave it to run unattended you should test it hard to make sure ... like any hot surface inside ... you don't want a fire hazard.

#3> Sense most are OEM designed for the controls to be on the cold side ... in your tinkering you either want to relocate the temperature sensors and controls ... or some other mechanism to allow the same effect ... ie ... when used to pump heat into a space ... you are not trying to regulate the air temperature of the cold side.

#4> Be aware that although any performance better than a SEER of 4.0 is more energy efficient than a resistance based space heater ... and many window AC units have SEER ratings many times better than this ... just remember that the Labeled SEER rating is not likely under the conditions you will be using it ... and it will perform differently under those different conditions ... so if say you have a unit with a SEER of 12 label ... don't be surprised if your effect SEER drops significantly ... but even a SEER of 8 ... is still twice as much heat joules of energy for the same amount of electrical joules as the best 100% efficient resistance based space heater.


Best of luck ... no matter what method of increased efficiency you explore.

[eco_generator]

I will probably pick up at least one radiator type heater to have something and then focus on sealing up leaky drafts in the ceiling/attic and foundation/frame interfaces, along with aluminum tape on the highly accessible ductwork in my basement.

The A/C heatpump tinkering can then be looked into.

Another idea in my head is humidifying the house so it will feel warmer at lower temperatures.

[ecomodded]

This idea of a reversed air-conditioner has me excited, I have a 500 watt window air conditioner.
If it does provide 4 x the heat per watt then a space heater it will turn my 500 w air conditioner into a 2000 w forced air heater. I likey that idea, It would heat my house on all but the most demanding cold days of the winter.
If i mounted it in my basement where i would not be disturbed by its noise i could leave it running on a thermostat all winter

Would ice build up be a problem ?

[MGB=MPG]

"Would ice build up be a problem ?"

could be .. there are full up heat pumps[cool & heat] available as window units .

as you may know the efficiency of a heat pump in heat mode falls off as the outside temps drop so use on *the coldest days * might not yield full efficiency .when its real cold here[not so very cold] the heat pump wants to switch on its axillary resistance , i have that disabled. in cold damp air they will build up ice on the coils outside
the heat pump senses that someway and heats the outside coil from time to time by reversing its function, quite a sight, at first glance one thinks the unit is on fire so much steam is emitted

[California98Civic]

Originally Posted by MGB=MPG

as you may know the efficiency of a heat pump in heat mode falls off as the outside temps drop so use on *the coldest days * might not yield full efficiency .when its real cold here[not so very cold] the heat pump wants to switch on its axillary resistance , i have that disabled. in cold damp air they will build up ice on the coils outside
the heat pump senses that someway and heats the outside coil from time to time by reversing its function, quite a sight, at first glance one thinks the unit is on fire so much steam is emitted

What brand and model pump are you using... and do you know the COP, SEER, or EER ratings? I ask because I am still shopping for one to heat and cool my whole house (not a space heater). I'm having trouble identifying and documenting the most efficient models.

More on topic: I just bought a Vornado VH101 space heater. It is cheap! And it will serve the small room, take the edge off the cold mornings for my wife, purpose. It has no thermostat, which I like, because I will put it on one of the timers I have and therefore have it turn on 20 or 30 mins before she wakes up. Some think it too small for a room, but I think they are looking for more than I need or else are in older climates than I am in Southern Cali.

[rmay635703]

Although drying isn't what you want but the cheapest most efficient space heater is a dehumidifier (heat pump), if you can locate it in your swamped basement and dry it out while also heating the whole house maybe it would be worthwhile?

[Ford Man]

I use a 22,000 BTU Monitor thermostatic controlled, closed heating chamber with circulation fan, vented kerosene unit which is considered a space heater, but I heat all of our 1400 sf house with it. I use to live in the Charlotte, NC area and now live in southwestern KY, in 17 years use I have never used more than 150 gallons of kerosene per heating season with the heater's thermostat set at 70*. The heater is set up to come on when the room temperature reaches the set temperature and stays on until the room reaches 4* above the set temperature. I have it located in the living room/kitchen (open area) so it keeps both the living room and kitchen at or near the temperature the heater thermostat is set at. The bedrooms are a few degrees cooler, but for my family that's an advantage since we like our sleeping area a little bit cooler. These heaters usually cost in the $1250-$1500 range when new, but often they can be found on ebay for much less. My son bought a used Monitor 22,000 BTU unit on ebay last winter for his 1000 sf home for $500 + $50 shipping. Monitor also makes a 40,000 BTU unit for larger homes. Installation consists of cutting one hole in the wall for the vent pipe, if I recall correctly the hole is either 2 1/4" or 2 1/2" diameter. The 22,000 BTU unit can be hooked up to a outdoor tank or the optional 1.33 gallon capsule tank that fits directly into the heater. The 40,000 BTU unit has to be hooked up to an outdoor tank. My Monitor will be 17 years old in January 2013 and the only work I've ever done to it was last winter when I replaced the burn mat and burn ring which amounted to less than $100. We had a mild winter here in KY last winter. I heated all winter on less than 85 gallons of kerosene while neighbors were paying $200-$300/month for electric heat. Monitor quit making kerosene units a couple years ago, but there are still a few new units available from suppliers. Toyotomi and Rinnia also still make similar units.

[MGB=MPG]

COP[ coefficient of performance], SEER,[seasonal energy efficiency rating] or EER[energy efficiency rating] ratings?
a Trane whole house heat pump Xl 16i . the energy star tag on it says the SEER is 17.0 , HSPF[heating seasonal performance factor] 8.5, other information i got [required to file for the gov. rebate]

indicates SEER 16.5, EER 12.5 ,COP 3.7 , HSPF 9

i would have to study a whole lot for any of that to have meaning to me .
something i understand better is that this unit has a scroll compressor that is set up to work as a 2 stage unit, when the demand is low it functions l as if it were 2/3 the size it is, releasing the compressed working fluid part way up the compression. thus using less energy .. i have a 4 ton unit , so on low demand it works like it was a 2.6 ton unit , then when demand is higher it ramps up. ..
likewise the air handler is a multi speed unit , some times the outside unit is operating at 2/3 and the air is just slightly sighing out of the vents, then as demand increases so does the outside unit and the CFM on the air handler increases , when its ramped up all the way the air fairly whistles out the vents. i have the info on the CFM somewhere in the document pack.
i think all the major manf. have similar units for efficiency.
costs more than a single stage . the one i wanted was a xl20i . it has 2 discrete compressors , a big one and a little one , when demand is low the little one runs , when high the big one , shucks maybe even both idk. however it cost even more . what i really wanted was a geothermal but the costs on those are outofsight. .
i replaced a 20 year old single stage 3.5 ton that failed to keep up with demand , it cooled the air pretty good[ showed 68F air out of the vents but did not move enough air. on the hottest days it would not keep up.
i have seen a considerable decrease in the power bill and stay cool , not to mention state and federal gov. gave me a substantial taX Credit , too bad it was just a 2 year program , this year i would have installed light pipes to illuminate the dark rooms with daylight vice running electric lights .

hope this helps
mrb

[IamIan]

Originally Posted by MGB=MPG

COP[ coefficient of performance], SEER,[seasonal energy efficiency rating] or EER[energy efficiency rating] ratings?
a Trane whole house heat pump Xl 16i . the energy star tag on it says the SEER is 17.0 , HSPF[heating seasonal performance factor] 8.5, other information i got [required to file for the gov. rebate]

indicates SEER 16.5, EER 12.5 ,COP 3.7 , HSPF 9

i would have to study a whole lot for any of that to have meaning to me .

All 4 units are just slightly different ways to measure the operating efficiency of the heat pump unit ... how many joules are moved per joule consumed.
That unit is listing numbers that indicate it is ~2.6x and ~4.0x better at moving joules of heat from Point A to Point B than a 100% Efficient Space Heater that just converts joules of electricity to heat... the lowest ~2.6x ( from the HSPF of 9 ) number is what it references for heating season expectations.

COP:
Is a direct real time Watt Output / Watt Input term
A COP greater than 1.0 is better than any resistance based space heat ... for those conditions.
COP is often used in engineering and scientific testing contexts.

EER:
Is a real time measure in BTU Output / Watt Input.
Because it mixes unit type of BTU and Watt ... it is basically just an adjusted COP ... COP * 3.14 = EER
EER is often used for labeling Air Conditioning Devices for Consumers.
Any EER greater than 3.14 is better than any resistance based space heater... for those conditions.

SEER:
Is also in BTU Output / Watt Input ... but is adjusted to be more of an average , to account for changes to performance under the different conditions during the tested seasonal conditions ... an effort to give a more accurate expectation of average operation under the tested seasonal conditions ... not yearly conditions.
SEER is often used for labeling Air Conditioning Devices for Consumers.

HSPF:
Is another performance ratio ... this one tries to give a single cumulative estimate for the whole operating season ... instead of just an average like the SEER or a snap shot like the EER and COP.
HSPF is often used for heating applications.
It's in BTU / Wh as units.
It can be converted to a entire season average COP.
HSPF * 0.293 = Entire Season Average COP
Any HSPF greater than 3.42 is better than any resistance based space heater , for those conditions.

[MGB=MPG]

ty
Seasonal energy efficiency ratio - Wikipedia, the free encyclopedia says :
when a heat pump operates near its most inefficient outside temperature, typically 0 °F (−18 °C), the heat pump will perform close to the same as a resistance heater.

Lower temperatures may even make a heat pump operate below this threshold, which is why conventional heat pumps include heater coils or auxiliary heating

i suppose if we ever see single digits here again i would be advised to enable the auxiliary heat.
the way i under stand the machine works is that when sensed temp falls a small # of degrees [3 ?] below the set or demand temp auxiliary heat is engaged.
i have the aux. heat disabled with software/hardware because the resistance heat elements are quite large , 3 banks .
i choose to let the heat pump struggle to maintain demand in winter w/o aux resistance heat . i now learn that this is not an economic decision when the temp falls below a critical temp. .

to return to the OP question . if the space heater is to be used on *the coldest days* and those cold days are below 0F resistance heat would seem to be the choice.
in my cold basement i have a quartz type radiant in the laundry area. it is nice since when turned on and one is in font of it it is as warm as a roaring fire. the downside is that these types of units are less safe than others and if not monitored a roaring fire might ensue.
..a good safety unit such as the oilfilled radiators would be more appropriate if continuous unmonitored usage is desired