Air Source Heat Pumps

lomb

albyota wrote: »

lomb, unless you know anything about Air to water heat pumps, it is foolish to even make comments like that....an 8kW system is absolutely all you need for a 3 /4 bed house ....I would guess that littletiger82's system might be over spec`d.......an average house with good insulation in the roof and cavity, good double glazing should have a heat load of between 7 and 10kW's.....eerrrm my house is a large four bed and I ripped out an 18kW condensing oil boiler...it now runs on an 8.5kW Ecodan for heating and hot water even with outside temperatures down to 10.2 degrees......

I do realise they are specced for heat loss however i doubt most people would accept 24/7 heating . Personally if i had a wet ashp i would add to that ashp splits in vital areas like master bedroom and living room for rapid heat up and control.

albyota

£80/month....no....that would be the case if it stayed at these sub zero and + 3 degrees days..... as it warms up....say above 5 or 6 this figure should decrease....obviously depends on your other electricity useage.

albyota

littletiger82 wrote: »

Albyota, thanks for all your help, having just bought my first place obviously money is tight and I just want to make sure I'm running it right as I have absolutely no previous experience with ASHP...

Yes, it's a new build
Yes, cooker and everything else is off the electric
Just little old me, but my mum did stay for a couple of weeks
Say 10 minutes per day in the shower? I'm assuming it's an 8kw, can't imagine the builders would have put in anything but the cheapest!
Washing machine on say twice a week, no tumble dryer.

Am I doing the right thing in keeping the heating on 24/7 to keep it at an ambient temp so that it doesn't have to work so hard to get back up to temp? Or should I be using it like a normal central heating system andhave it on and off throughout the day?

ten minute showers :eek:......well for running everything, I wouldn't worry too much at the moment..... is the Ecodan running radiators or UFH....?

littletiger82

albyota wrote: »

ten minute showers :eek:......well for running everything, I wouldn't worry too much at the moment..... is the Ecodan running radiators or UFH....?

radiators!

albyota

littletiger82, in these colder weeks....just drop the thermostat down a bit to 18 or so...when you go out.....if your away for longer periods.... turn it off, but because of the lower temps....typically 50 -55 degrees, you would normally time it to come on say an hour before you come home...to get the house up to temperature.

albyota

lomb wrote: »

I do realise they are specced for heat loss however i doubt most people would accept 24/7 heating .

24/7 heating is a misconception I'm afraid......ASHP can be run and controlled just like any other central heating system, however they have been designed to be installed into houses with low heat losses.

it is wet underfloor heating that is designed for 24/7 operation with any type of heat source.


Personally if i had a wet ashp i would add to that ashp splits in vital areas like master bedroom and living room for rapid heat up and control.

Why on earth would you do that..... unless you have the desire to overspend on the unnecessary.... do you tow a spare car behind your main car???

albyota

The Mitsubishi Ecodan Homeowners Manual

http://ecodanlive.mitsubishielectric.co.uk/pdf/ecodan%20home%20owner%20manual.pdf

Andy_WSM

lomb wrote: »

I do realise they are specced for heat loss however i doubt most people would accept 24/7 heating . Personally if i had a wet ashp i would add to that ashp splits in vital areas like master bedroom and living room for rapid heat up and control.

That's just nuts!

I have a 5KW Air to Water pump heating a 2 bed bungalow + water tank. It has, for the most part, worked great through the Winter, with the exception being a run of nights where the outdoor temps dropped to -10C, which the system was not spec'd, or manufactured, to cope with! The solution (thanks Richard for this one!) was to turn on the immersion heater to provide 3KW of supplemental heating in the system.

My pump runs 24/7 if it needs to, but each radiator has a separate zone control, so the living room is only heating in day time & evening and the bedrooms only heated in the evening & night.

24/7 heat to me is a major plus, not a disadvantage.

My Winter bills were rather large, but still 20% less than last Winter - and this Winter has been considerably colder!

lomb

Andy_WSM wrote: »

That's just nuts!

I have a 5KW Air to Water pump heating a 2 bed bungalow + water tank. It has, for the most part, worked great through the Winter, with the exception being a run of nights where the outdoor temps dropped to -10C, which the system was not spec'd, or manufactured, to cope with! The solution (thanks Richard for this one!) was to turn on the immersion heater to provide 3KW of supplemental heating in the system.

My pump runs 24/7 if it needs to, but each radiator has a separate zone control, so the living room is only heating in day time & evening and the bedrooms only heated in the evening & night.

24/7 heat to me is a major plus, not a disadvantage.

My Winter bills were rather large, but still 20% less than last Winter - and this Winter has been considerably colder!

Fair enough, but perhaps you are retired or work from home? I for one have no interest in paying for heating im not using be that at night or when im out at work during the day. I like the concept of split air for instant heat and digital temperature control as well as superior COPS due to it being a larger market therefore more manufacturer money goes into R+D. In any case I shall bow out of the argument and post back as soon as my splits are up and running to report back on controllability as well as comfort.

albyota

lomb, I really think you are a little confused as to the difference between air to air and air to water, and why 24/7 is reccomended for some and not others......it is a complete mixed bag of options open to all.... quite a few of us on this forum are in the industry and have been installing / specifying for years....but have been discussing the merits/pitfalls, pro's n' cons of all types for a long time.....good luck with your MHI Splits....