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

treecol · 16 November 2018 at 1:17PM

Again, thank you. We had this installed https://www.appliancesdirect.co.uk/p/eiq-12k12kc24kwminv/electriq-eiq12k12kc24kwminv?refsource=APadwords&refsource=A%20%20padwords&gclid=EAIaIQobChMI8rbL7JfB2QIVKrvtCh3UZQv%20%20iEAYYASABEgJJ6fD_BwE

at the recommendation of a board member here just so you know what we have. We have left the unit on 16c when we went out a while ago when we had that brief cold snap. I'm going to try leaving it on 18c when we're out and 16c at night compared to switching it on and off and see how the heat and energy compares. The room is entirely separated from the main house by doors so almost a sealed unit. Our bungalow is late 60's and well insulated but this extension is 90's and has a single wall on one side which is the draughty garage and a huge vaulted ceiling with limited insulation. There is also an entire wall of glass at one end too so whilst the house only drops to around 17 at night on the coldest nights, this room would be sub-zero.
we will try your suggestions and report back,
Thanks again.

matelodave · 16 November 2018 at 1:46PM

Ours is Air to water feeding underfloor heating so not at all comparable with an air to air unit but it's pretty easy to monitor it's consumption using an energy monitor to sse how tweaking your comfort and set back operations affects the system power consumptions. see here for what ours looks like https://www.energyhive.com/dashboard/dave (it's monitoring the whole house electrics but you can clearly see what the heatpump is doing). We set back to 17 degrees overnight and have different temperatures in different rooms at diffferent times of the day. Some nights it comes on and others it doesn't and it works harder on colder nights or days.

However as said above air source heat pumps are very sensitive to outside temperatures as well the internal temperatures. So if it's cold out side it has to try and create heat from a lower base so has to work a lot harder - I've seen our external unit with quite a build up of frost on it especially on days when it very damp as well as cold. It gives out a big burst of vapour when it goes into derfrost mode.

Ours probably has a significantly slower response time than an air-air unit, so if we let the house get cold it takes several hours to get it back up to temperature. even more if the house gets really cold - we have to set it to come on at least the day before we return home if we go away in the winter. I can temporarily increase the flow temperatures to try and speed it up but with a corresponding very high increase in energy consumption.

richardc1983 · 16 November 2018 at 2:03PM

treecol wrote: »

Again, thank you. We had this installed https://www.appliancesdirect.co.uk/p/eiq-12k12kc24kwminv/electriq-eiq12k12kc24kwminv?refsource=APadwords&refsource=A%20%20padwords&gclid=EAIaIQobChMI8rbL7JfB2QIVKrvtCh3UZQv%20%20iEAYYASABEgJJ6fD_BwE

at the recommendation of a board member here just so you know what we have. We have left the unit on 16c when we went out a while ago when we had that brief cold snap. I'm going to try leaving it on 18c when we're out and 16c at night compared to switching it on and off and see how the heat and energy compares. The room is entirely separated from the main house by doors so almost a sealed unit. Our bungalow is late 60's and well insulated but this extension is 90's and has a single wall on one side which is the draughty garage and a huge vaulted ceiling with limited insulation. There is also an entire wall of glass at one end too so whilst the house only drops to around 17 at night on the coldest nights, this room would be sub-zero.
we will try your suggestions and report back,
Thanks again.

Do you mean 16c when you are out & then 18c when you are at home? There would be no point having it warmer when you are not there and then cooler when you are there. That would give no benefit at all.

Could you also clarify where the 2 units are installed as the link you sent shows 2 indoor units on 1 outdoor unit. Also how large are the rooms the units are installed in? I think you said it installed in your hall so assuming normal hallway size I think 3.5kw per unit is reasonable.

lovesgshp · 17 December 2018 at 2:08PM

Do not know if this will help anyone with air - water units. It is based on the IVT units, but is a good guide.
Unfortunately you will have to use a translation program as it is in Italian.

https://www.geotherm.it/blog/6-mosse-per-preparare-la-tua-pompa-di-calore-per-inverno/

treecol · 14 January 2019 at 4:51PM

Just wanted to post an update to help those who may be considering one of these units. Having now been using them for the last quarter, taken a meter reading and had our bill, we've actually used less electric than last year! We've had the units on between 7am and 10pm set to 18 degrees c. It's not been cold enough to leave on overnight but the room has kept warm.
Overall we're really happy with units and how warm the keep the room (which is huge with a vaulted ceiling) and it's cost us no more than last year when the room was hardly heated rendering it unusable. I'd recommend them highly.

Moorlander · 17 January 2019 at 10:07PM

Hi folks, I have been following this latest thread with interest, not least of which because I have installed the 12k BTU equivalent.

Ours is in a 28sqm conservatory, albeit with stone walls on 3 sides. It still seems somehow counter intuitive to be heating it when we are not using it. Especially since we live in the chilly Peak district. We are only using it in the week for a about an hour in the morning and 3 hours in the evening. Our comfort temperature in 19 degrees , is it worth heating it to 16 degrees all the time for that level of useage, including overnight?

One final thing that might be worth mentioning, our outdoor unit ended up under the bathroom window, with warm moist air inevitably coming out of the window following a shower etc . I wonder how if at all that will effect the performance?

Many thanks for reading this and any replies would be gratefully read.

richardc1983 · 17 January 2019 at 10:48PM

Moorlander wrote: »

Hi folks, I have been following this latest thread with interest, not least of which because I have installed the 12k BTU equivalent.

Ours is in a 28sqm conservatory, albeit with stone walls on 3 sides. It still seems somehow counter intuitive to be heating it when we are not using it. Especially since we live in the chilly Peak district. We are only using it in the week for a about an hour in the morning and 3 hours in the evening. Our comfort temperature in 19 degrees , is it worth heating it to 16 degrees all the time for that level of useage, including overnight?

One final thing that might be worth mentioning, our outdoor unit ended up under the bathroom window, with warm moist air inevitably coming out of the window following a shower etc . I wonder how if at all that will effect the performance?

Many thanks for reading this and any replies would be gratefully read.

You should do the electric readings just to check how much it's using and then see if your happy with it.

4 hours usage in 24 hours is similar to how long I'm home in the week when using my central heating in the house so there's cause to maintain a base temp.

Also the moisture in the bathroom air following a shower contains heat energy, this will be sucked into the unit and it will "recover" the heat from the steam which is a good thing and there isn't going to be that much of it so will be minimal but waste not want not.

The steam when it's really cold may freeze up on the back of the unit and contribute to the unit eventually defrosting but it's not a big issue not like you've a cooling tower pouring steam into the atmosphere.

matelodave · 18 January 2019 at 9:45AM

As suggested, the only way to see what energy it's consuming is to monitor it.

An energy monitor clamped onto the electrical input will allow you to measure how much it's using and when and enable you to optimise it's use. Something like an Owl or Efergy, especially one with the capability of downloading the info to see or view the consumption graphically over a time period - like this https://www.energyhive.com/dashboard/dave

treecol · 21 January 2019 at 9:14PM

Moorlander wrote: »

Hi folks, I have been following this latest thread with interest, not least of which because I have installed the 12k BTU equivalent.

Ours is in a 28sqm conservatory, albeit with stone walls on 3 sides. It still seems somehow counter intuitive to be heating it when we are not using it. Especially since we live in the chilly Peak district. We are only using it in the week for a about an hour in the morning and 3 hours in the evening. Our comfort temperature in 19 degrees , is it worth heating it to 16 degrees all the time for that level of useage, including overnight?

One final thing that might be worth mentioning, our outdoor unit ended up under the bathroom window, with warm moist air inevitably coming out of the window following a shower etc . I wonder how if at all that will effect the performance?

Many thanks for reading this and any replies would be gratefully read.

We found, after enquiring here, that it's much more ecconomical to provide constant heat as the unit will in effect be using less electric. We've found the room maintains a lovely ambient temperature. We don't have to turn the heat above 18 degree now, where as when we switched it off and on, we had to set the heat higher to bet it to come up to temperature.
We haven't been cold enough over night to leave it on 16 all night, but I think looking at the forecast we will soon.
As per my comment up thread, having just had out electric bill, we cannot believe how ecconomical these units are. Hope that helps a little?

helpjack · 23 January 2019 at 10:01PM

The job for this year is to renovate our conservatory. It's approximately 6m X 3m with a thick polycarbonate roof glass on two sides and blank plastic on the side facing next door. All with drawf walls.

My plan was to replace the plastic roof with blue glass, replace the plastic wall with brick and heat it with one of these air to air inverters. I think a 12000 BTU one would be sufficient.

Do you think that would work. If we don't replace the plastic wall there is nowhere to hang the indoor unit.

I want it to be a dining room and playroom. I can't wait to get it useable.

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

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