ASHP's and the maze of info

richardc1983

Yep...

However the splits we know over here are known as ductless splits over there!

thechippy

That's just the yanks being difficult.......:D

Cardew

richardc1983 wrote: »

That is true, I was just referring to the cost of gas vs electricity in this country.

Gas is more expensive than electric in America why a lot of people use Heat pumps over there.

Whoa.

I have a place in the USA - with a heat pump.

Gas is not more expensive than electricity.

The problem is that the price of gas is so volatile - it can soar in the winter when demand is high.

There is a fixed price for the delivery of gas to your property and then yo pay for gas. At the moment including all charges(I just checked) it is 72 cents a therm so about 2.5 cents/kWh or 1.5pkWh.

I pay about 11 cents/kWh for electricity(7p/kWh)

However in States that require Aircon, heat pumps are normal and few houses have natural gas piped to them.

We have had this discussion before about gas v ASHPs in UK and I suspect that when you take into account Hot water and overall COPs of systems there is little to chose between the two.

Also as mention earlier, I can have my heating off all day and with 30+kW heating my radiators to 80C in double quick time, the house gets warm very quickly.

To get houses to heat with an ASHP you need to have them running much longer and heat is wasted if you are not in the house.

richardc1983

Cardew it takes me house to warm up from 14C about 2.5 hours to raise the temp to 22C thats with outdoor temps of what we currently are experiencing so all I do at that point is bump the fan speeds upto high and were sorted.

That is with an air to air system which is the best way to deliver the heat unless using underfloor heating, but then you dont get the cooling.

thills

Are you guys saying that air to air is better at space heating than air to water? Its one hell of a lot cheaper to install, and the cost difference would pay for DHW by electricity for 20 years (for 2 people).

Cardew

thills wrote: »

Are you guys saying that air to air is better at space heating than air to water? Its one hell of a lot cheaper to install, and the cost difference would pay for DHW by electricity for 20 years (for 2 people).

Also keeping doors open to bathrooms, bedrooms etc.

Cardew

richardc1983 wrote: »

Cardew it takes me house to warm up from 14C about 2.5 hours to raise the temp to 22C

Exactly!!

How long with conventional Gas CH? --- 30 mins???

clockworks_2

I am new to all this and was under the impression that heat pumps were super efficent and use a third of the energy conventional systems eg GCH and eletric heaters use.

Is this not the case?

I have an air source heat pump that vent hot air out of vents in the ceiling, and cold air too. (albeit it when it's working!)

thills

[QUOTE=Cardew_Also_keeping_doors_open_to_bathrooms,_bedrooms_etc.[/QUOTE]

-- not interested in doing that, would have to split the indoor units into 3 zones at least. Just wish I had gas & could install something "normal"

Cardew

clockworks wrote: »

I am new to all this and was under the impression that heat pumps were super efficent and use a third of the energy conventional systems eg GCH and eletric heaters use.

Is this not the case?

I have an air source heat pump that vent hot air out of vents in the ceiling, and cold air too. (albeit it when it's working!)

Heat pumps are super efficient when compared to normal electrical heating.

Indeed they can use a third of the energy of 'normal' electrical heating.

Essentially they work in the same manner as a fridge. Except they work by extracting the heat from the outside of your property instead of extracting heat from inside your fridge.

This means that for one unit of electricity you can get as much as 4 or even 5 unit's worth of heat; that gain is called the COP(Co-efficient of Performance)

However as the outside temperature decreases so you get a lower COP so perhaps a reasonable overall COP might be 3.

However it certainly doesn't mean that you get that advantage over gas CH as gas generally costs less than a third of the price of electricity.

There are lots of other factors - for and against - to consider in the gas v ASHP comparison, but generally there is not much to chose in running costs between heating with gas or heating with an ASHP.