UPDATED: Air Source Heat Pumps/Air Con - Full Info & Guide, is it cheaper to run than mains gas?

richardc1983

thechippy wrote: »

A fixed speed can work down to low ambients just as well as an inverter.

An inverter compressor is simply a compressor who's speed can be varied by the inverter board, so it can ramp down as the load reduces, or increase as the load rises.

There is no difference in the efficiency of each as such, it's just the way they are controlled.

The better manufacturers use inverter systems, as when correctly applied are more efficient than fixed speed as they match the load to that required. As the load either increases or decreases, the compressor will try to match the load required. This is more efficient than a simple on/off scenario of anything fixed speed.

It's the same as modern boilers that use a modulating gas valve. The boiler will ramp up/down as required by the load.

It was my understanding that inverter compressors can ramp up further than their designed duty to give extra capacity when needed.

thechippy

If you run any compressor beyond it's designed duty, you are asking for problems.

A fixed speed just runs flat out all the time. However, it's actual load changes due to other factors. If for example in a/c mode the ambient temp rises, the condensing temp and pressure rises and so does the load on the compressor, so it will draw more current.

Basically, despite the fact it's fixed speed, the comp load as such will still vary.

richardc1983

thechippy wrote: »

If you run any compressor beyond it's designed duty, you are asking for problems.

A fixed speed just runs flat out all the time. However, it's actual load changes due to other factors. If for example in a/c mode the ambient temp rises, the condensing temp and pressure rises and so does the load on the compressor, so it will draw more current.

Basically, despite the fact it's fixed speed, the comp load as such will still vary.

I think it runs it at a higher rate for a short time i.e half an hour before going back down to its max design speed.

muckybutt

muckybutt wrote: »

Thought id add my two penneth, we have just had a Heatking 9000i ASHP installed by way of a council grant and im well impressed, complete strip out of the old oil system and all the old pipework.
Unit 2Kw input 9Kw output, Kingspan cylinder for hw.
It is so quiet it didnt even wake us up this morning like the old thing used to, and weve copious amounts of hot water on tap now, our house is dated back to 1850, mid terrace cottage only single glazed tho due to being listed so im looking at fitting secondary glazing now. With the heating on i was looking at the meter and it goes slower than when the immersion used to be on, also installed is a back up / top up heater when outside temp falls below 2 deg to assist system, all fully pressurised so mains pressure hot water as well.
I would certainly recommend this to anyone thinking of putting ASHP in wether in an old house or a new one.
http://www.heatking.co.uk/bwarmi.html

Update on this P O S.

Weve had it in a while now and its goto be the WORST decision we've made having this put in.
We were advised to leave it running 24/7 for it to be more economical - which we did, the alarm bells rang 6 months after it being fitted when the electricity supplier rang us up asking if we were expecting a big bill ? when we got the bill we were bowled over £800 for 70 days use.
Since then we only have it on in total for 4 hours a day and itsstill costing us £200 a month.
If anyone wants to buy an ASHP then ive got one going cheap...buyer to collect. We're getting rid of the bloody thing and getting a wood burner stove, far far cheaper to run.

Cardew

I have cut and pasted your post and put it on this thread:

https://forums.moneysavingexpert.com/discussion/2968958

zeupater

muckybutt wrote: »

Update on this P O S.

Weve had it in a while now and its goto be the WORST decision we've made having this put in.
We were advised to leave it running 24/7 for it to be more economical - which we did, the alarm bells rang 6 months after it being fitted when the electricity supplier rang us up asking if we were expecting a big bill ? when we got the bill we were bowled over £800 for 70 days use.
Since then we only have it on in total for 4 hours a day and itsstill costing us £200 a month.
If anyone wants to buy an ASHP then ive got one going cheap...buyer to collect. We're getting rid of the bloody thing and getting a wood burner stove, far far cheaper to run.

Hi

Agree with the wood burner route. Make sure you get a decent make then get your wood early and well seasoned, along with a good log store .....

Z

bushyh

Dear All I'm back! Builder has agreed to take out pump and put in gas boiler. They are talking about running pipe work down side of house from pumps current position to garage where they will put the boiler. This is apparently to avoid taking ceilings down but I suspect is also cheaper. I am of the view that although it will create more mess in my pristine little abode that I should get a proper job done and run the pipes inside - any views on that one?

Cardew

bushyh wrote: »

Dear All I'm back! Builder has agreed to take out pump and put in gas boiler. They are talking about running pipe work down side of house from pumps current position to garage where they will put the boiler. This is apparently to avoid taking ceilings down but I suspect is also cheaper. I am of the view that although it will create more mess in my pristine little abode that I should get a proper job done and run the pipes inside - any views on that one?

A result.

Re the pipes, I would have thought running pipes outside would contravene Building Regulations - which are pretty strict on heat conservation/insulation etc. Have a word with local council.

arty68

Hello,

Just thought I would share my running costs as I'm happpy with them . For the last 3 months my Electricity bill was £350 which I don't think is to bad considering we are an all electric house using the tumble dryer,washing machine and dishwasher daily.

so over all I'm very happy with my ASHP and this winter I was very glad I wasn't on oil anymore.

richardc1983

arty68 wrote: »

Hello,

Just thought I would share my running costs as I'm happpy with them . For the last 3 months my Electricity bill was £350 which I don't think is to bad considering we are an all electric house using the tumble dryer,washing machine and dishwasher daily.

so over all I'm very happy with my ASHP and this winter I was very glad I wasn't on oil anymore.

What system do you have installed? CAn you spec it for us? Thanks.