Night Storage Heaters vs Electric Wet Central Heating

[Dunton]

So, on a practical level, how easy is it to instal a heat pump system?

Given a 3 bed semi that I don't want to disrupt too much (no more than if installing the EWCH), with only electricity, no garage or space for one, but plenty of land to the rear.

How do we transfer the heat to the rooms? Is it still a case for the heat pump to heat the thermostore instead of electric boiler, and the thermostore supplies heat for CH and domestic hot water? so still rads and pipework?

The installation costs look high but the savings per year look impressive.

 

[Steve]

installation is expensive, they have to be professionally installed. Cost roughly 2-3 times what a gas central heating system costs.

Outside, you have 2 options.

* A standard air conditioning compressor unit or 2. Similar to those on shops and offices. These tend to ice up in winter, but defrost on commercial units is very fast.

* A ground loop. This is basically the coil thats normally in the compressor unit but spread out inside the earth. The compressor then sits inside somewhere. This option is more expensive.

The outside part and the indoor part are connected by pipes which circulate fluid. Ground systems only circulate water and anti-freeze outside. The standard ones circulate refrigerant between the indoor and outdoor units.

Indoors you also have a few options.

*A wet central heating system, which circulates water through radiators, like a standard GCH system. This is not preferred, as the water isn't as hot. Rads needs very hot water. Cant run cold. It also introduces losses where the heat is transferred to the water.

*A fanned air conditioner unit which sits on the wall and blows the air over the refrigerant lines into the room, either hot or cold. You'd need a few of these, but several can run off one powerful compressor. (preferred option in my opinion)

*Underfloor heating - again, water is circulated underfoot. This is preferable to radiators, as UFH needs lower temperatures to work. But cannot run cold.

*Central Air. Like in american homes, this system has a central air handler with ductwork to each room. Can run hot or cold.

Some systems allow a combination of the above, for example:

Downstairs - UFH in the kitchen, blowers in the living room, conservatory and dining room.
Upstairs - central air unit mounted in the loft distributing air to all 4 rooms.

Or instead of a combination on one compressor, have one compressor for each method of heat.

Sky's the limit. (Well, 100 amps is the limit, but you get my drift)

 

[plugwash]

* A ground loop. This is basically the coil thats normally in the compressor unit but spread out inside the earth. The compressor then sits inside somewhere. This option is more expensive.

but better, ground temperature is more constant (which generally means less different from your desired indoor temperature) than outside air temperature so ground source is generally more efficiant, it is more expensive to install though

 

[Dunton]

mmm ok. So what do these fans on the wall look like?

A radiator is pretty unobstrusive and can sit behind things (not ideal). How big are the pipes connecting them to the 'heat source'?

 

[Steve]

For the refrigerant pipes, your talking the size of the drain pipe under the kitchen sink. That is, all the piping and wiring will fit within that diameter. For an idea, look behind your fridge. See the pipes there? Think 3-4 times that size plus insulation plus a couple of wires and a drain hose.

If you want standard radiators, they will run off hot water, piped to the heat source like you would to a gas boiler.

 

[Dunton]

Pretty bulky then. Running costs seem real good, but not as convenient as installing the EWCH.

What about the fanned wall heaters inside? are they bulky? How do you get the pipework to them?