We are shortly taking over another shop for our charity - it is about 1000sq ft, ceiling is about 10-12 feet high and it has no heating.
Normally in our shops we go for electric blowers installed in suspended ceiling grids where we have it or conventional radiators if we have gas and boilers.
Some shops don't have these and so we have resorted to wall mounted 3kw heaters dotted about the shop but these are dear to run, noisy and not too durable.
This new shop has nothing going for it in the way of efficiencies and unfortunately we cannot put in a suspended ceiling unless we pay several thousands to relocate the sprinkler system.
Any thoughts on the most efficient type of electric heating we could use here? Another issue is that it is quite a tight shop so we would be looking to utilise every foot of wall space for selling!
Any bright ideas?
|
|
in terms of efficiency one type of electric heater is as good as another in that they all convert 100% of the electricity into heat. The efficiency comes from how you control the heat by means of thermostats and timers. Depend on what sort of heating you prefer really. I work in a place with overhead radiant heaters whichbeing direct radiant heat make you feel warmer quicker than convected heat you get from a radiator.
|
|
It might be worth checking out commercial PTC heaters, this type of heater is fast and efficient.
|
As others have said, they're all the same efficiency wise. 1 watt in equals 1 watt out. The only exception is to have a heat pump, which can produce 3 to 4 times the heat energy compared to input, although thjis starts to drop as the temperature drops. But, you have to take into account the capital cost, which is very high compared to regular cheap, reliable heaters.
The pump I've got in the workshop has a COP of 5, so for each watt in, I get 5 watts of heat out. But, the COP value is calculated at 7 degrees outside temp. At -12 the COP is about 2, and at - 20 it,s about even.
|
>> As others have said, they're all the same efficiency wise. 1 watt in equals 1
>> watt out.
Not strictly true. Yes one watt in, one watt (well almost - nothing is 100% efficient) out but where does the one war out go? Heaters vary enormously in how and where they radiate or convect the heat.
Last edited by: Zero on Tue 3 Feb 15 at 20:41
|
Actually the efficiency of an electric heater in producing heat from electricity is 100% because anything other than heat produced such as light, motion, etc produced by the heater will at some point is dissipated as heat.
The way the heat is used will of course affect the way the occupants of the room feel. some
people find radiant heat less stuffy that convected heat. Fan heaters,by warming the air
make you feel warmer quicker but these things are subjective and don't really have to do with the efficiency of the device in the technical sense.
|
>> Actually the efficiency of an electric heater in producing heat from electricity is 100%
Nothing is 100% efficient.
>> do with the efficiency of the device in the technical sense.
There are loads of technical issues in radiating, convecting and dissipating heat. You need to look at if from the other direction - cooling.
|
No machine is 100% efficient but turning an electrical current into electricity is simply turning one sort of energy into another. Energy cannot be lost or destroyed.
|
>> No machine is 100% efficient but turning an electrical current into electricity is simply turning
>> one sort of energy into another. Energy cannot be lost or destroyed.
Its not all turned into heat (some is lost in noise, some is lost in non heat generating emf, some is returned to earth) and some the heat is not heat that can be usefully radiated or convected.
|
|
But all those other forms of energy will eventually be dissipated as heat and the conversion of current to heat is therefore 100%
|
>> But all those other forms of energy will eventually be dissipated as heat
Of course they wont, the emf could go on to infinity depending on its frequency. Some of the noise will converted back into electricity.
Last edited by: Zero on Tue 3 Feb 15 at 22:44
|
It will all eventually end up as heat
To quote a well known engineer"
"You cannae change the laws of physics!"
|
>> Normally in our shops we go for electric blowers installed in suspended ceiling grids where
>> we have it or conventional radiators if we have gas and boilers.
>> This new shop has nothing going for it in the way of efficiencies and unfortunately
>> we cannot put in a suspended ceiling unless we pay several thousands to relocate the
>> sprinkler system.
Go urban and trendy. don't put in the suspended ceiling, but install the heaters anyway. Leave all the services on view.
Have to say Bobby I am impressed. Not only are you sales manager, you are real estate and building services manager as well.
|
|
Best thing you can do for your electricity bill is make sure the front door is a good fit and add a decent quality door closer if it's not already got one. Electricity bills in shops can be horrendous.
|
I daresay I should have clarified the "efficient" part of my question.
I was meaning efficient as in will heat up a shop that has high ceilings as efficiently as possible as opposed to making sure that every watt in was a watt out so to speak.
Re door, we always try and fit a blower over the door to act as a curtain heater.
This is a new shop to us and if it proves successful then we may well spend money next year and putting in an insulated ceiling but just now we can't justify the price on an unknown quantity.
Never thought of Zero's idea of still going for the ceiling heaters but just hanging them in a chain or something from the ceiling.
I also wonder if this is one of these shops that will work out cheaper to try and keep heating on all the time rather than just shop times to build up a heat in the shop. Even just a few of the oil filled radiators switched on at nighttime to stop the place going really cold.
|
>> I daresay I should have clarified the "efficient" part of my question.
>>
>> I was meaning efficient as in will heat up a shop that has high ceilings
>> as efficiently as possible as opposed to making sure that every watt in was a
>> watt out so to speak.
That's effectiveness you are talking about. Say what you like about efficiency, some electric heaters are more effective than others! Some radiant heat tends to feel warmer and more immediate than the convected variety - and if you have high ceilings convectors might take a while to feel warm whilst they are warming up that space over everybody's head.
There are two local village halls, both have high roofs. One has gas ch to radiators. The heat needs to be on for a couple of hours before it warms up. The other has downward facing electric radiant heaters hanging maybe 9 feet above the floor. Ten minutes after switching those one you feel toasty.
|
Ah the old keep it a bit warm cos it costs less argument beloved of some heating bods (I'm not calling them engineers cos they're not).
It's basically codswallop. Keeping low heating on when non-occupied can sometimes result in a lower bill, but the reason is because the place is not so cold, you don't come in, turn all the heating on and because you got cold, raise the temperature higher. The maths of heat loss is very simple, temperature difference, inside versus outside is the key.
|
>>I also wonder if this is one of these shops that will work out cheaper to try and keep heating on all the time rather than just shop times to build up a heat in the shop.
If a container/house/shop were perfectly insulated, then once it had reached a temperature required there would be no need to input further heat.
Therefore, the heat you need to put in is equal to the loss of heat.
The rate of loss of heat is directly proportional to the temperature differential between the inside temperature and the outside.
It follows that it must be cheaper to warm up a cold place, rather than keep it warm!
QED?
|
mega SQ
>> It follows that it must be cheaper to warm up a cold place, rather than
>> keep it warm!
>>
>> QED?
>>
100% correct..
Last edited by: VxFan on Wed 4 Feb 15 at 12:50
|
>> >> It follows that it must be cheaper to warm up a cold place, rather
>> than
>> >> keep it warm!
>> >>
>> >> QED?
>> >>
>>
>> 100% correct..
I spent years telling my dad this, and he didn't disagree with the theory (the higher the temperature gradient, the greater the heat loss) but he always said experience showed it didn't work that way, or at least that it wasn't worth the messing about.
Obviously it would be if you were away for a week at a time, but with daily comings and goings the theoretical cost falls and other factors might come into play, though the cost difference will still be there unless you "overshoot" every time you reheat the house.
Also if your house is very well insulated, the extra cost of leaving it on all the time, instead of just most of the time, could be very small indeed.
We were away from Sunday afternoon until last night. I left the heating on for 6.30-8.30 and 16.30-22.30, and the Rayburn on low 24/7 for the kitchen, which has no radiators.
We came home last night to find the boiler had blown out at some point and the only tolerable room in the house was the kitchen. An hour and a half later it was till only 13C in the sitting room and I had to light the fire. The heating (normally off 22.30-06.30) stayed on all night. Lovely and warm now!
|
>> mega SQ
>> >> It follows that it must be cheaper to warm up a cold place, rather
>> than
>> >> keep it warm!
>> >>
>> >> QED?
>> >>
>>
>> 100% correct..
>>
Not so sure about your "100% correct "assertion. We have a holiday apartment that we rent out here in Austria. It's generally well insulated, but has a concrete floor, over which is laid parquet flooring. Below that floor are garages, which are obviously unheated. The main living areas is heated by a huge night storage heater
If we let the apartment get cold, by leaving the heating switched completely off when it's unoccupied, it takes days for it to feel properly warm again due to the uninsulated floor, and the concrete acting as a huge fridge. During that period, the heating needs to be full on. If it's left on at a low setting, it needs less heat and less time to get it up to a comfortable temperature for our paying guests. So overall, I reckon it's cheaper to keep it ticking over than keep turning it on and off, but our needs are perhaps slightly different.
As an aside, I've toyed with the idea of infra-red heating panels, which seem to be becoming popular, where the occupants and contents of the room are heated rather than the air, but it's difficult to get a handle on the comparative costs. There no option other than electricity unfortunately.
|
So overall, I reckon it's cheaper to keep it ticking over than keep turning it on and off, but our needs are perhaps slightly different.
Only 'cheaper' if one adds in your time. As a straight forward use of electricity goes, as others have already pointed out, no.
|
>>Have to say Bobby I am impressed. Not only are you sales manager, you are real estate and building services manager as well.
You forgot IT and chief van driver as well...............
|
>> >>Have to say Bobby I am impressed. Not only are you sales manager, you are
>> real estate and building services manager as well.
>>
>> You forgot IT and chief van driver as well...............
Thats CIO and Transport manager in management speak.
|
|
Thought I could maybe have got Logistics in there somewhere??
|
I could sell you some 200w bayonet cap bulbs. Heat & light combined. Long drop pendant fittings.
Come buy. Cum bye.
|
>> Come buy. Cum bye.
Coom by ah, sing a glamour-free bunch of religiosos boringly.
Will this be censored too? Is there a glamour-free religioso sneaking about in the site, with censorship privileges?
Tchah!
|
|
When we first moved into our house the only source of heat in our bathroom was some sort of huge light bulb - wonder if it was as much as the 200w !!
|
I thought Glasgow central heating was a tea light under an upturned flowerpot. I will check, I am just off to Glasgow. :)
A good DPF cleaning run along the M80.
Last edited by: Old Navy on Wed 4 Feb 15 at 08:58
|
|
We also sell 250W & 400W infra red BC reflector bulbs. Ideal for rearing chicks & whelping puppies. Some of our more rural customers use them for heating in smaller rooms. Honestly!
|
We were in Nice last week, and outside eating areas were commonly heated quite effectively by heaters such as these:
www.dimplex.co.uk/assets/kb/technical_specification/0/QXD_Spec_Sheet.pdf
You could feel the warmth from about 3 metres away.
|
|
Interesting neiltoo - I have also been looking at Infra Red heaters today which seem to claim the same thing ie. heat the person rather than the air.
|
>> Interesting neiltoo - I have also been looking at Infra Red heaters today which seem
>> to claim the same thing ie. heat the person rather than the air.
They had those on the old station concourse in Northampton to stop the RPI's on the barrier getting exposure. Very effective but I don't know what they cost to run.
|
Don't know what French electricity costs, but the heaters were on all lunchtime, and evening, whether there were diners/drinkers or not.
The manufacturer or an electrical installer should be able to give you an idea of positions, numbers, and consumption.
|
Efficient electric heating - CGNorwich
