Air Source Heat Pumps - Any good in practice?

lovesgshp

Only just saw this posting, as it was not on the alternative fuels board.
With a ASHP, then you can do a retrofit, even with existing radiators. You just need a buffer tank, to hold a higher water temperature, and bypass controls on the rads if you are using TRV's to maintain flow rates.

weewards

lovesgshp wrote: »

Only just saw this posting, as it was not on the alternative fuels board.
With a ASHP, then you can do a retrofit, even with existing radiators. You just need a buffer tank, to hold a higher water temperature, and bypass controls on the rads if you are using TRV's to maintain flow rates.

Hi thanks to everyone for their replies to date, there is a fair bit of reading to do yet then...

With regards to the retrofit option as suggested above, surely this would be very inefficient as I believe a ASHP system would be more efficient with Large radiators installed as the heat generated by the heat pump is not as high as that produced by a conventional boiler, so a larger surface area is needed to achieve similar temperatures in the home?

lovesgshp

weewards wrote: »

Hi thanks to everyone for their replies to date, there is a fair bit of reading to do yet then...

With regards to the retrofit option as suggested above, surely this would be very inefficient as I believe a ASHP system would be more efficient with Large radiators installed as the heat generated by the heat pump is not as high as that produced by a conventional boiler, so a larger surface area is needed to achieve similar temperatures in the home?

Not that true. We do quite a lot of retrofits, without changing radiator size. In fact, most say that they have a more even room temperature with their existing rads, than they did before.
You will get a more steady temperature in the rads, than with a conventional system.
Buffer tank to help even out the temperatures when they drop outside.

c13pep

As a prerequisite to my own retrofit ASHP installation a whole house survey was done taking in to account the temperature I required it to achieve and the existing Worcester Bosch boiler system. After subjecting all the measurements etc. to a comprehensive calculation on the heating engineers laptop programme and then a second recalculation by the ASHP manufacturer to confirm the results a system rehash was the outcome. The majority of radiators were increased in size in order to accommodate the lower flow temperatures, a hybrid 12Kw system was the outcome. The external unit pumps refrigerant up to an internal heat exchanger 8m away in my loft, thus with thinner external piping the losses are less than when pumping hot water thro` external circulators. The internal unit is only marginally larger than the outgoing boiler it replaced. The internal unit also houses the pump and the electronic control units, this system works very well.