Infrared panels for heating

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#1992548 10-Apr-2018 09:46

I assume the profit margins for IR panels are much higher than for heat pumps. The former are some resistive wire mounted in a panel of some sort, whereas the latter are relatively complex machines being sold into an extremely competitive environment. I could imagine a $1000 IR panel costs $50-$100 to make, and a $2000 heat pump maybe $1000? Similarly installation for IR consists of a connecting wire and four screws, compared to pipe runs etc etc for heat pumps.

Nett result is IR panels offer high "value add" (ie profit) for the supplier and installer, so they are marketed more vigorously - just like HRV and nitrogen in your tyres.

BlueShift

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#1992604 10-Apr-2018 10:45

shk292:

IR panels sound like a total con to me - it's the same heating effect as the glowing electrical filament in front of a shiny reflector that your granny had in her front room 40 years ago. 1200w is not an adequate heat source for an average lounge room - I have the smallest size heat pump (2.5kw?) and that's just about enough on a cold (for Auckland) winter evening.

We had 3 heat pumps installed in our house (one per living area) shortly after we bought it, 12 years ago for a toral cost of $6800 - one was a simple "back to back" install, whereas the others were more complicated with pipe runs about 15m. Servicing cost since then has been zero. I haven't worked out the ROI, but my wife likes a warm house and I'd be surprised if we haven't achieved a 200% ROI by now.

You can't get away from the fact that heat pumps give you around 250-300% efficiency, whereas any other heater gives you 100%. No marketing speak can change this.

The big 'gotcha' with working out your ROI on a heatpump compared with any other form of heating is the extra 2-3 months a year you'll end up using the heatpump when your other heaters are gathering dust. Heatpumps are called that as they can move heat in either direction - in or out of the room. So you'll end up using it as an aircon though summer. Which is a big selling point for them, obviously. But it means that your running costs per annum can't be compared 1-1 with a heater. Sure the heater is less efficient per hour, but you're only using it for half the hours that you're running the heatpump.

shk292

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#1992611 10-Apr-2018 10:58

BlueShift:

The big 'gotcha' with working out your ROI on a heatpump compared with any other form of heating is the extra 2-3 months a year you'll end up using the heatpump when your other heaters are gathering dust. Heatpumps are called that as they can move heat in either direction - in or out of the room. So you'll end up using it as an aircon though summer. Which is a big selling point for them, obviously. But it means that your running costs per annum can't be compared 1-1 with a heater. Sure the heater is less efficient per hour, but you're only using it for half the hours that you're running the heatpump.

I don't think that's a fair "gotcha" - I'd look on the cooling functionality as a complete bonus to the primary purpose of heating; you don't have to use the heatpump for cooling so I don't think you should include energy used for cooling in any ROI calculation for heating costs. As it is, we probably use ours for cooling for a few hours on a handful of days per year - another bonus of the Auckland "boring" climate which spends most of its time between 15 and 25C.

timmmay

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#1992644 10-Apr-2018 11:49

I'd say there's only a couple of months a year we don't use the heat pump. We heat starting any time from April, through to about November. From about November to March we often use air conditioning, but not usually as much as we use heating in winter. Having said that, this summer we left the air conditioner on all day for quite a few days, it was a hot summer though.

I don't much care what they cost to run, within reason. From memory We pay about $50/week in summer and $75/week in winter, two heat pumps, average sized house. That's a small price to pay for comfort IMHO.

BlueShift

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#1992763 10-Apr-2018 14:21

shk292:

BlueShift:

The big 'gotcha' with working out your ROI on a heatpump compared with any other form of heating is the extra 2-3 months a year you'll end up using the heatpump when your other heaters are gathering dust. Heatpumps are called that as they can move heat in either direction - in or out of the room. So you'll end up using it as an aircon though summer. Which is a big selling point for them, obviously. But it means that your running costs per annum can't be compared 1-1 with a heater. Sure the heater is less efficient per hour, but you're only using it for half the hours that you're running the heatpump.

I don't think that's a fair "gotcha" - I'd look on the cooling functionality as a complete bonus to the primary purpose of heating; you don't have to use the heatpump for cooling so I don't think you should include energy used for cooling in any ROI calculation for heating costs. As it is, we probably use ours for cooling for a few hours on a handful of days per year - another bonus of the Auckland "boring" climate which spends most of its time between 15 and 25C.

That's the problem, they don't use the energy for cooling in the calcs. Which means, unless you take into account that you may be using the unit anywhere from a handful of extra days to a couple of extra months, you will not get the annual savings you are being led to expect.

Wash

57 posts

Master Geek

#1992766 10-Apr-2018 14:28

We have an IR heater on our deck. In that situation, if you're close enough to it, it works ok.

I wouldn't bother with one inside. Because it heats objects, you have to be close and line of sight and it would take forever to heat the actual space. You'll find the place will still feel cold if the items in the room feel cold to the touch e.g. a stone benchtop always makes a room feel colder as it feels colder to the touch than a formica benchtop.

Additional reasons to not bother with one:

- no cooling/dehumidifying capability

- 1.2kw of heating seems very little for a 21sqm space

- no thermostat control

- are there any issues with that much IR exposure?

- A small capacity heatpump would be more efficient energy wise and while more expensive, it should be 2x more expensive, not 4-5x

If you do go with one, please report back though. I'm sure many people would be keen to know if it works out!

wombus

107 posts

Master Geek

#1992864 10-Apr-2018 17:07

I'm considering putting in a LHZ convector heater with heat retention tablets for a smallish bedroom, you can pick up a 1500w for $569.99 from BBQs Direct which will heat a room 15m2. This is a spare bedroom only used occasionally and I can't really see its worth of paying more for the investment of infrared and i'd like to think the heat retention will help keep the unit off some of the time with the thermostat.

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timmmay

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#1992904 10-Apr-2018 18:22

wombus:
I'm considering putting in a LHZ convector heater with heat retention tablets for a smallish bedroom, you can pick up a 1500w for $569.99 from BBQs Direct which will heat a room 15m2. This is a spare bedroom only used occasionally and I can't really see its worth of paying more for the investment of infrared and i'd like to think the heat retention will help keep the unit off some of the time with the thermostat.

Why not an oil heater?

shk292

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#1992958 10-Apr-2018 20:11

timmmay:

Why not an oil heater?

The LHZ ones have special unobtainium trioxide coated heat bricks which dramatically improve heating efficiency by altering the bernoulli air flow around the heated area

Unfortunately the global unobtainium market is high at present, hence the $450 price premium over an oil-filled heater

Aredwood

3885 posts

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#1993047 10-Apr-2018 23:32

wombus:
I'm considering putting in a LHZ convector heater with heat retention tablets for a smallish bedroom, you can pick up a 1500w for $569.99 from BBQs Direct which will heat a room 15m2. This is a spare bedroom only used occasionally and I can't really see its worth of paying more for the investment of infrared and i'd like to think the heat retention will help keep the unit off some of the time with the thermostat.

The advertising of those heaters is just a whole heap of marketing BS. They are simply a convection heater with a high thermal mass. Which is exactly the same as an oil column heater.

Because of this kind of marketing fluff. The government should put mandatory energy star ratings on all electric resistance heaters. With all of the labels stating 1 star energy efficiency.

@wombus just buy an oil column heater or other convection heater from the warehouse or another appliance store. As you will never save any money on running costs by buying an expensive convection heater compared to a cheap one.

wombus

107 posts

Master Geek

#1993049 10-Apr-2018 23:46

Aredwood:
wombus:
I'm considering putting in a LHZ convector heater with heat retention tablets for a smallish bedroom, you can pick up a 1500w for $569.99 from BBQs Direct which will heat a room 15m2. This is a spare bedroom only used occasionally and I can't really see its worth of paying more for the investment of infrared and i'd like to think the heat retention will help keep the unit off some of the time with the thermostat.

The advertising of those heaters is just a whole heap of marketing BS. They are simply a convection heater with a high thermal mass. Which is exactly the same as an oil column heater.

Because of this kind of marketing fluff. The government should put mandatory energy star ratings on all electric resistance heaters. With all of the labels stating 1 star energy efficiency.

@wombus just buy an oil column heater or other convection heater from the warehouse or another appliance store. As you will never save any money on running costs by buying an expensive convection heater compared to a cheap one.

Thanks Aredwood its hard to research and compare eggs with eggs but i now gather that say 1kw power = 1kw heat output unless you go for a heatpump would that be correct?

The other reason an oil column heater was unfavourable is I want the heater to sit flush and as asunobtrusively as possible on the wall to save floorspace.

Aredwood

3885 posts

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#1993053 11-Apr-2018 01:09

wombus:
Thanks Aredwood its hard to research and compare eggs with eggs but i now gather that say 1kw power = 1kw heat output unless you go for a heatpump would that be correct?

The other reason an oil column heater was unfavourable is I want the heater to sit flush and as asunobtrusively as possible on the wall to save floorspace.

Yes, 100% correct. Resistance heaters always give you 1KW of heat for every 1KW of electricity they use.

Another common dodgy marketing trick, is taking a low wattage heater, and quoting its running costs in the form of cents per hour compared to a different heater. But it is only cheaper due to it putting out less heat.

Yet another dodgy trick is taking 2 heaters of the same thermal mass, but with the same wattage. And timing how long they take to heat a room. The heater with the lower thermal mass will be faster to heat the room. But only because it has less mass to heat. But the manufacturer will then claim that the faster speed equals higher efficiency, which it doesn't.

An exception to the rule above actually applies to dehumidifiers. Every litre of water that a dehumidifier removes from the air. You get 0.6 KW/Hr of free heat. Reason is due to the latent heat of water.

Although not an option for you as you need more heat. Dehumidifiers can be a good option to reduce heating costs if installing a heatpump is not possible. And with the benefit of less dampness as well.

Aredwood

3885 posts

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#1993054 11-Apr-2018 01:16

@wombus Maybe something like this heater would suit?

https://www.bunnings.co.nz/euromatic-2000w-panel-heater_p00012439

It claims to be wall mountable. And I see that 1KW and 1.5KW versions are also available.

raytaylor

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#1994424 11-Apr-2018 20:21

A good infrared heater is about 85% efficient.

That means for every 1kw of power you put in, about 850 watts of heat comes out.

They dont necessarily heat the air, they require a non-reflective, dark mass to convert the infrared energy into heat. This is why they can heat your body, furniture and other objects, but not the air around you. The air is heated by the mass giving off heat.

==============================

A standard resistive heater is approx 99.9% efficient

That means for every 1kw of power you put in, about 999 watts of heat comes out.

They are the cheapest form of heater, come in various forms such as

- Oil column heater
Slower to warm up, silent, constant heat output

- Fan heater
Instant heat, loud, intermittent heat output

- Convection heater
Somewhat fast heat, silent though some have a fan option, intermittent heat output, designed to be installed against a wall

================================

A heat pump is approx 300-400% efficient

That means for every 1kw of power you put in, about 3500 watts of heat comes out.

They are more expensive up front, but they only cost 1/3rd as much to operate compared to a resistive or infrared heater.

It can take a few minutes for a heat pump to provide heat, but they can be very quiet which is something Mitsubishi Electric advertise for their floor level upright models.

A heat pump will usually have a hard time working when it is -5deg or colder outside. They are most efficient when the outside and inside temperature is the same.

Heat pumps come in three shapes.

- High wall mounted, best for cooling but is the most common type installed in NZ
- Floor wall mounted, best for heating but will do a great job cooling. Typically more expensive but most agree they look better and they are generally quieter due to the larger surface area for heat transfer inside them.
- HVAC Style / in-attic where air is sucked and returned to each room via a central heat transfer unit using ceiling vents. Most common in other countries where central heating is common or larger houses.

Heat pumps can also be used for heating water used for swimming pools, house hot water supply, underfloor heating etc.

Its also our cleanest form of heating. 80% of the electricity in NZ comes from renewable sources.

But there is a down side to heat pumps

They are not very well suited for very small rooms with closed doors. The high installation cost and their inability to scale heat output down to a very low amount means it can often be more efficient to just use a small fan heater in a small room.

But I always suggest go the heat pump route if possible.

Ray Taylor

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razor2000nz

217 posts

Master Geek

#1995073 12-Apr-2018 21:13

Ive been looking into IR panel heaters as well, but for use in the bedrooms, wondering if they would be good for those kind of rooms, the info on the website says the surface of the panel can reach 100 degrees, so maybe not so good for kids etc

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