what is the most efficient type of central heating?

johnwallace

What is the most efficient type of so called central heating for a home, disregarding the cost of the fuel, between the following?

Gas boiler and radiators?

Warm air heating using gas?

Warm air heating using electricity?

Electric boiler and radiators?

Electric storage heating?

Not including hot water

given that there are 5 identical houses with identical heat loss and all houses are maintained at the same temperature for 15 hours a day from 8am to 11pm and the occupants were also identical.

Which system would use the least and most kWh of fuel?

Andy_WSM

johnwallace wrote: »

Which system would use the least and most kWh of fuel?

The all electric solutions would use the least KWh as there are no flu losses - all electric heating is 100% efficient.

However; electric costs 3 times more than gas, so if you are not really looking for efficiency but looking at running costs then electric probably isn't the way you want to go?

You haven't mentioned heat pumps - a far more efficient means of using electricity to produce heat as they can be 3 or 400% efficient (sometimes even more!).

johnwallace

You haven't mentioned heat pumps -

I know, for the very reason you did, how can something be 400% efficient?

Is that not physically impossible?

OK how much electricity in kWh would storage radiators use to keep a home warm for a 15 hour day from 8am to 11pm? I do realise that they will not actually be consuming electricity at that time.

Swipe

johnwallace wrote: »

I know, for the very reason you did, how can something be 400% efficient?

Is that not physically impossible?

OK how much electricity in kWh would storage radiators use to keep a home warm for a 15 hour day from 8am to 11pm? I do realise that they will not actually be consuming electricity at that time.

A heat pump doesn't use electricity to generate the heat per se. It uses it to drive a compressor and fans. The refrigerant going through the coils produces/transfers the heat and that heat output is greater than the electricity drawn to drive the unit e.g 1KWh in 3KW out

Storage heaters tend to be 2-3KW so multiply that by the number required. Taking thermostats into account lets assume they are drawing power for 5 of the E7 hours depending on how high you have them on and how cold it is. That should give you a rough idea.

Cardew

johnwallace wrote: »

I know, for the very reason you did, how can something be 400% efficient?

Is that not physically impossible?

OK how much electricity in kWh would storage radiators use to keep a home warm for a 15 hour day from 8am to 11pm? I do realise that they will not actually be consuming electricity at that time.

How efficient is a Hydro electric power station that uses no fuel?

A heat pump converts the heat available in the outside air(or ground) and 1 kWh of electricity can produce up to 4 kWh of heat in a property. That said there are a lot more disadvantages to heat pumps that their advocates gloss over.

On your question of storage radiators, it will take the same amount of kWh from storage radiators to heat your house as it would with any other form of electrical heating.

However on a winter day it might take, 150 kWh to heat a house and you would need a lot of storage heaters for that capacity; and they wouldn't be able to release the heat evenly over the day.

Stick to gas with radiators!!!

Pincher

Also, what about the possibility of using Economy 7 to drive heat pumps to heat up a thermal store?

I think it's possible to use the Gledhill type cylinder, where the potable mains water passes through the cylinder in a pipe loop, never mixing with the stagnant storage water, which needs just a little bio-suppressant to stop bacterial growth.

Obviously we need to use a bigger cylinder size at 40 degrees, compared to storing heat at around 70 degrees. About 1000 litres, I guess. At 40 degrees, it's ideal for under floor heating. Rural locations tend to be off the gas grid, but it also means that they have more space outside for an insulated tank, but ideally you want to bury it in the ground, or put it in the basement if you have one.

I see scalable rectangular modules of 500 litre each, you just hook up as many as the house needs.

Owain_Moneysaver

Electricity is, overall, only 50% efficient as the losses in the generation/transmission network are huge.

Gas boilers have some flue losses, but almost insignificant. They are on the other hand very controllable, so you don't waste heat where or when it's not needed. Storage heaters have the poor overall efficiency of electricity plus they are awkward to control, leading to excess or insufficient heat.

bengasman

The most efficient form of heating "normal" houses is gas central heating with radiators.
Electric heating, including heat pumps is more expensive.

mrnomoneybags

I thought Warm Air heating are supposed to be very good, As warming air to say 21* is cheaper than warming water to say 70* to then warm the air ?

Obviously newer warm air systems are better than old.

samtheman1k

Your question if flawed. The efficiency of a heating system is irrelevant, what is important is the running cost. You have to take into account the price per kWh to make a fair comparison. (plus things like CO2 etc. if you are into that kind of thing too!)


Electric powered by an air turbine at the end of the garden is infinitely efficient (not in terms of Physics of course)!

Owain_Moneysaver

samtheman1k wrote: »

Electric powered by an air turbine at the end of the garden is infinitely efficient (not in terms of Physics of course)!

But not actually a lot of practical use, unless you only want your heating to work about 1 day in 4.