Air Source Heat Pumps

albyota

clc5 wrote: »

I was about to spend £1700 replacing my G rated combi gas boiler but after reading about the upcoming Renewable Heat Incentive scheme I'm thinking an Air Source Heat Pump providing heating and hot water might be a better investment. My well insulated 3 bed semi has 10 radiators. I don’t have a water tank. Can anyone give me a rough idea of what I would expect to pay for a decent quality ASHP system? Also, what about maintenance costs? And, apologies if this seems a daft question, do I have to get new pipe work and radiators and all the disruption that entails? Any advice would be appreciated.

No you don't need new pipework, calculations for Rad sizes would be done to see if any need upgrading, but you are not looking at a massive amount to do this, (c £600) the system comes with a new mains pressure unvented DHW cylinder but that can be fitted in an integral garage, utility room, airing cupboard or attic. most systems are low or maintenance free. ballpark for 3 bed house around £7k fully installed.

clc5

albyota wrote: »

No you don't need new pipework, calculations for Rad sizes would be done to see if any need upgrading, but you are not looking at a massive amount to do this, (c £600) the system comes with a new mains pressure unvented DHW cylinder but that can be fitted in an integral garage, utility room, airing cupboard or attic. most systems are low or maintenance free. ballpark for 3 bed house around £7k fully installed.

Thanks for that.

bernidefish

i live in austria where the winter temperatures can go to -20 at night. We are looking at air source het pump and under floor heating combined with PV panels on the roof. The panels would offset the extra electricity used by the pump.
my worry is that when we need the heat the most, ie, winter, the outside air is coldest. Will the system work efficiently??
Any hints or experiences will be gratefully accepted.

richardc1983

bernidefish wrote: »

i live in austria where the winter temperatures can go to -20 at night. We are looking at air source het pump and under floor heating combined with PV panels on the roof. The panels would offset the extra electricity used by the pump.
my worry is that when we need the heat the most, ie, winter, the outside air is coldest. Will the system work efficiently??
Any hints or experiences will be gratefully accepted.

There will be heat pumps designed specifically for your cold climate in Austria... my advice on when you need it the most would be to purposely oversize the unit so even when its at its lowest output its still providing the requirements of the house heating etc.

When you size it base it on the worst case scenario even if majority of the year its not worst case scenario.

So if average temp all year is not -20C but a few weeks of the year are at -20C then base your overrall system capacity on this temperature.

albyota

bernidefish wrote: »

i live in austria where the winter temperatures can go to -20 at night. We are looking at air source het pump and under floor heating combined with PV panels on the roof. The panels would offset the extra electricity used by the pump.
my worry is that when we need the heat the most, ie, winter, the outside air is coldest. Will the system work efficiently??
Any hints or experiences will be gratefully accepted.

Hi, firstly.... minus 20 at night.....(when you are asleep) for how long? how many Days/weeks? In Austria (correct me if I'm wrong) your houses have far better insulation levels and good quality tripple glazed windows. Most good quality Air Source Heat Pumps (Mitsubishi, Daikin, Sanyo amongst others) work down to minus 25 degrees. With flow temperatures of 35 - 40 (avg 37) for use with underfloor heating systems, they work at their most efficient at lower water flow temperatures, and can still look after the domestc hot water (60 degrees). Underfloor heating when installed correctly, with the thermal mass of the concrete screed acts like a storage heater so (Heat loss) will not be noticed when the unit goes into defrost. (4 mins/hour)
Solar P.V will have to be grid tied but with the correct array i.e. amount of panels, this should offset the extra electricity usage.

Alfie1939

I'm 70 and in a 4 bedroom detached house with an old Ideal 80 floor mounted gas boiler and DHW tank.

I was thinking of replacing the gas boiler with an ASHP but having read your inputs I feel that may not be viable.

How about the Atmos Combinair which appears to be a gas boiler and an ASP.

Any advise welcome. Alfie.

albyota

Alfie1939 wrote: »

I'm 70 and in a 4 bedroom detached house with an old Ideal 80 floor mounted gas boiler and DHW tank.

I was thinking of replacing the gas boiler with an ASHP but having read your inputs I feel that may not be viable.

How about the Atmos Combinair which appears to be a gas boiler and an ASP.

Any advise welcome. Alfie.

The cheapest option is to replace with a new condensing system gas boiler and DHW cylinder for around £3k - £3.5?, a 4 bed detached is no problem with ASHP's but rad sizes need looking at to check their output at lower temps, (some may need upgrading) The solution could be the Sanyo ECO CO2 9kW system (many satisfied customers) heats water to 65 degrees, can be used with existing rads but will cost in the region of £8.5K - £9K fitted.
Atmos Combinair looks like a sizeable bit of kit (needs room). It is most suited to new build so that all the ducting from kitchen and bathroom extracts can be routed to the unit with large ducting, wouldn't have thought it would be cost effective to retro-fit.

How much is the Atmos Combinair???

Alfie1939

Thanks albyota,

Yes I think 9K is a lot at my age, Pity hate staying with gas.. I only got the leaflet on the Atmos Combinair and haven't looked at the atmos web site so I don't know the price however from what you say it wouldn't be suiatble for me. Thank you,
the search continues. Alfie.

Swipe

My experience over the last 12 months:

I had 2 Daikin 3.5KW air to air heat pumps installed on 15th May last year in my 3 bed detached bungalow. One in my front room and one in my bedroom. I also have a woodburner in the front room which I planned on only using at weekends. However, due to the really cold winter this year I ended up keeping the stove lit constantly for about 2 months. I used £90 of smokeless fuel and a around 1cubic metre of logs (which cost me nothing). I used the heatpump in the front room to supplement the stove on very cold nights. Using my electricity consumption from the last two weeks as a guide for the next 4 weeks, I estimate that my total annual electric bill (heating and immersion heater for dhw) will be just £300 (single person at work all day). So approx £400 total heating costs including coal.

Not bad considering the winter quarter in my last house (3 bed semi with two storage heaters) was at least £300. I had considered buying another heatpump for my kitchen but I figured the outlay compared to the hour or so I used the 2KW fan heater when in there cooking didn't really justify the cost. I also didn't use the heatpump for cooling in the summer as we only had about 2 hot days last year and in my bungalow the bedrooms tend to stay cool (north facing)

Surfer

Our housing association has informed us that they may be replacing our storage heaters with air sourced heat pump so that may be good news for us.