Is an ASHP the way to go for us?

carolynw

We have a 5 bedroom house 235M2 which has an oil boiler that needs replacing and provides hot water and runs our underfloor heating throughout the house.  The heating is set to frost protect at 5degrees all through the year as the house is plenty hot enough.   We have solar panels to offset a very expensive to run aga, hence the need to never run the heating.  We have 0.8 rated windows and a lot of solar gain which also explains why our  underfloor heating is set to frost protect.  We are thinking of replacing our oil boiler with a Samsung ASHP.  Is this the best solution? 

Netexporter

You should get a good SCOP as you have underfloor heating already. You'll probably have to change the hot water cylinder to one with a larger heat exchanger coil, to allow for the lower flow temperature. You may also need to change any zoning arrangements in the UFH system, as heat pumps work much better with a large volume of water in circulation. You can use weather compensation, rather than internal thermostats in a more open loop type system. 

carolynw

Sorry @Netexporter but I don't understand whether we need an ASHP at all?  We are not using our underfloor heating system at all just keeping it on frost protect.  Should we just get a new emersion heater?????   Thanks 

matelodave

it begs the question, why are you asking?

If you dont need heat then why replace the boiler? and why consider a heat pump. Perhaps you really need to decide what you need or want because your question at 18:15 and then subsequent post at 19:19 dont make any sense

An immersion heater will just heat your hot water, and if thats all you want then get rid of the boiler. and done with. There is an option of a heatpump hot water cylinder which will just heat your hot water but thats not the question you asked.

carolynw

matelodave said:

it begs the question, why are you asking?

If you dont need heat then why replace the boiler? and why consider a heat pump. Perhaps you really need to decide what you need or want because your question at 18:15 and then subsequent post at 19:19 dont make any sense

An immersion heater will just heat your hot water, and if thats all you want then get rid of the boiler. and done with. There is an option of a heatpump hot water cylinder which will just heat your hot water but thats not the question you asked.

But don't immersion heaters cost a fortune to run and could we connect the underfloor heating to one even if we don't use it?  

koru

This seems like a good review of oil vs heat pump: https://so-eco.co.uk/air-source-heat-pump-vs-oil-boiler/

Your house must be very well insulated if you rarely need the heating on. Together with the underfloor heating, this pairs really well with a heat pump. You'll probably only need a very small heat hump.

The only reason not to switch is that you don't use much heating, so you'll get proportionately less benefit from the investment in a new heat pump than a more normal house. And heat pumps are usually a bit less efficient in heating water for the taps than for room heating.

Alnat1

It seems the "very expensive to run" aga might be the item that needs replacing, as it appears this is where most of your heat is coming from. What fuel does it use and how much?

An ASHP/electric cooker could supply all your heating, hot water and cooking needs and may be cheaper to run than aga/oil boiler. It would allow all the property to be fully heated and not just the area around the aga.

Reed_Richards

Essentially you must use your oil boiler just to provide yourselves with hot water.  Your underfloor heating does not seem to do anything useful whilst you actually occupy your house and you could probably achieve frost protection with a couple of electric radiators should you be away from home in winter.

To heat your hot water you could just use an immersion heater.  This could be expensive to run unless you have a night-rate electricity tariff.  But the installation cost would be minimal; indeed perhaps you already have one.  Or you could install a cylinder with a dedicated heat pump.  This could cost around a third of the running cost of an immersion heater but you have to offset the installation cost. 

FreeBear

Reed_Richards said: To heat your hot water you could just use an immersion heater.  This could be expensive to run unless you have a night-rate electricity tariff.  But the installation cost would be minimal; indeed perhaps you already have one.

And what you certainly do not want to do is use that hot water to heat the house (even just frost protection). It will cost a ruddy fortune and be rather inefficient.

I'd look at getting rid of the aga and installing an alternative heat source. A heat pump may be the cheapest to run depending on the property. You'd need an in depth heat loss survey and some solid recommendations based on that.

HHarry

You have solar panels.  Install an immersion heater and time it to come on during the day with your free electricity.

paul991

do not use a timer use a i boast or similar