What's the cheapest way to heat n have hot water?

[BigBurner]

Of course. My point is, that over a year, the running cost for heating and cooling with the heat pump is the same as just the heating with gas, so effectively there is no extra cost incurred by the cooling. It's "free"

I don't think you said that. Also air sourced heat pumps in winter cannot raise the water to DHW levels, >60C, and electric resistance heating has to compliment. Is this cost taken into account?

Why buy something that costs about 3 to 4 times more to install?

I know this is the problem at the moment and I did state that in my original post.

In a commercial situation where you do "need" heating and cooling the heat pump may be the answer and the payback in install capital cost may be recouped pretty quickly.

The whole lot: installation cost, servicing, running, etc, all have to be calculated quite accurately to see if it is worth it.

Dismissing heat pumps out of hand as some have here is silly. There are many types, sourcing heat from:

• air,
• air (with warm extract air running over evaporator),
• ground (just below surface),
• ground (deep bore),
• ground (wet most of time),
• ground (dry most of time),
• still water,
• running water.

The best is running water. Heat pumps are service free, so a saving over a boiler again. Good heat pumps are simple - just fridge components.

 

[stem]

Air sourced heat pumps in winter cannot raise the water to DHW levels, >60C, and electric resistance heating has to compliment. Is this cost taken into account?

Yes, the building with the heat pump doesn't use it to heat stored water at all, that's provided by immersion heaters using off peak electricity, and it was all included in the annual energy costs that were used for comparison.

The heating system isn't wet anyway, it emits air via ceiling diffusers, hence the cooling facility in the summer.

 

[jackthom]

Nowadays there's loads of options..........combi's, heat stores, etc etc.

So, let's say I have a 3 bed middle of terrace solid wall 1930's house with double glazing and 4" insulation in loft and it has a gas supply. Taking into account the boiler parts n servicing costs too (my old combi needed lots of parts n labour! so it's efficiency was flawed by it's ineffiency!). Then assuming there are two adults n two children in there, what should I install to keep my wallet as fat as possible!

First I'd strongly recommend increasing this to at least 12" while you're still thinking about what type of heating system to install.

 

[BigBurner]

Air sourced heat pumps in winter cannot raise the water to DHW levels, >60C, and electric resistance heating has to compliment. Is this cost taken into account?

Yes, the building with the heat pump doesn't use it to heat stored water at all, that's provided by immersion heaters using off peak electricity, and it was all included in the annual energy costs that were used for comparison.

The heating system isn't wet anyway, it emits air via ceiling diffusers, hence the cooling facility in the summer.

You will find it is semi-wet. A wet copper coil in the ductwork. More savings could have been had if the heat pump heated DHW and resistance heaters assisted (the heat pump can be on off-peak too).

 

[BigBurner]

Nowadays there's loads of options..........combi's, heat stores, etc etc.

So, let's say I have a 3 bed middle of terrace solid wall 1930's house with double glazing and 4" insulation in loft and it has a gas supply. Taking into account the boiler parts n servicing costs too (my old combi needed lots of parts n labour! so it's efficiency was flawed by it's ineffiency!). Then assuming there are two adults n two children in there, what should I install to keep my wallet as fat as possible!

First I'd strongly recommend increasing this to at least 12" while you're still thinking about what type of heating system to install.

Not only that, seal up the loft with a sealed hatch door and all pipes and cables sealed that pass into the loft too (ceiling roses). Heat air losses to the loft can be substantial.