Does Anyone Here Use An Air Source Heat Pump with hot air ventilation?

flygti

Hi All

My first post!

Just looking for guidance.

Live in a 3 bed semi with old storage heaters. Initially unbearably cold but after switching to economy 10 (heatwise) it is bearable but still pretty poor.

Have being doing loads of research on central heating systems (no gas in the village) but can find very little info' on one option I am considering.

LPG/Oil pretty expensive to run with high initial costs and major trauma installing a wet system.

GSHP/ASHP wet system. Expensive initial investment, low running costs but once again trauma installing wet system.

Aircon/ASHP??? I can install a Daiken 5MXS90E outdoor condensor unit (ASHP) feeding 5 x Daiken FLXS25B wall/inverter units (3kw heating each) to replace 5 x 2.5kw storage heaters.

They quote 4:1 efficiency on the heat pump but living in the real world I would expect 2 -3 times. Instead of running the storage heaters on 10hrs off peak we will run the a/c units for probably 8 - 10hrs peak but with the gain in efficiency hopefully compensating for the increased peak rate.

So.... basically if I get better running costs it would be a bonus but if they were the same I would still be happy with the added comfort factor of having this heating.

Million dollar question... does anyone have any experience with this kind of heating system (heatpump running hot air heating) and if so am I being realistic about running costs etc and are they effective in keeping everybody warm in winter (with the option of cool in summer of course)?

Allegedly maintenance is pretty low (1 service a year £125)

Total cost including install is around £5k

Thanks for your time.

Cardew

Welcome to the forum.

I take it you have read this thread.

http://forums.moneysavingexpert.com/showthread.html?t=702257

Obviously this is for a 'wet system' but it is an excellent thread discussing ASHPs.

The modifications to your house to fit 5 units would surely entail major building work and the noise would be a big problem; not only to you but your neighbours??

There is no doubt that they work, and a COP of 4 is achievable, but of course not in winter when you need the heat.

flygti

Thanks Cardew... I have read that thread (and every other bit of ASHP I can find). There just seems to be a lack of real life info' about ASHP and hot air distribution.

The noise is a concern but this is specifically for domestic installs and apparently very quiet... Sales talk of course which is why I am hoping somebody else has something similar installed!

The units attach to the ceiling/wall so minimal construction work and they can run the 1/4" piping behind the skirting apparently... sounds a lot easier than a wet system and a few k cheaper.....

bobmedley

I've got two air-con units that are heat pumps & I run them in Winter no problems at all - they supply prodigious amounts of heat down to -9 deg C (mine are Toshiba) and their latest models work down to -15 deg C which should not be reached in any normal winter in the UK. Note I have oil CH also, so I don't depend on them for all house heating.

You are paying around 2.5p per kw heat gained, so these are pretty much the cheapest way to heat a house - I think gas is slightly more than that now? Mine run as inverters, - it's not 'on or off' and nothing inbetween, so you just basically pick a temperature & the unit runs at varying speed to get there.

The £125 service sounds right - they are cleaned & the gas/oil is checked & there is nothing else to do for the rest of the year.

Noise is not an issue - the indoor unit is whisper quiet & the outdoor unit just hums a little, usually not enough to disturb anybody.

Also remember you will be nice & cool in the Summer with all this global warming......:cool:

flygti

Thanks Bob.

I am struggling to understand why this form of heating is not more popular with people who don't have gas, especially when you consider most modern office blocks etc are heated this way.

bobmedley

Well remember they won't heat your water & compared to gas the running costs are probably around the same or slightly cheaper - but if you had a choice most people would go with the gas devil they know.

Compared to oil/LPG/electric though, they stack up very well indeed and if I was building a new house off the gas mains, then I would go for the air conditioners/heat pumps perhaps with a touch of solar to heat the hot water.

On running costs, they seemed to have had little impact on my electricity bill as whilst they consume a kilowatt each, because they are inverters they do not run all the time.

Looking at your situation above, the storage heaters would consume 12.5kw, to give 12.5kw of heating but the heat pumps would give 15kw of heating for only 3.75kw input - I don't know if you have Economy 7, but even if you did (around 5p now) then the heat pumps are still going to be half the price of running the storage heaters & are a lot more flexible (you can get heat on demand).

Have to state that the cooling you get in Summer is very welcome indeed (they are on now!):cool: