Heat pump / inverter DIY

richardc1983

I agree with you Steve, for me I see the costs daily on my energy meter and I hate to see it that way as if im in all day and its going all day long I think christ ive spent £4 today on electric. but then when it averages over the month its not that bad at all!

stevehead

richardc1983 wrote: »

I agree with you Steve, for me I see the costs daily on my energy meter and I hate to see it that way as if im in all day and its going all day long I think christ ive spent £4 today on electric. but then when it averages over the month its not that bad at all!

Yeah I reckon the xmas / new year break set a UK record for residential heating costs.
7.6C outside at 1 am down south 'ere now Rich what a scorcher!

richardc1983

6.1C up here Steve, 2.8C with the windchill thrown in!

mech_2

stevehead wrote: »

Those aren't straws, they add up to a huge proportion of the running costs. You can't ignore the electrical consumption 'cos to me that's a whole months worth of heating.

I'm not ignoring it. I suggested taking it into account way back in message #133. But it's not useful information on its own without figures for the whole of both systems in order to make a complete comparison. Bringing in more small variables is just confusing the issue when we don't have the basics.

And comparing it to a month's heating with an ASHP is a bit dubious. It's comparing different things. My combi boiler provides me with all my hot water too. At 90% efficiency. How efficient is your hot water heater? I suspect more money is going out through its flue than my boiler uses for its electrics. At least the electric usage helps heat the house a little.

Secondly, I thought the consesus here at MSE was that the annual gas service check was essential, or am I mistaken? Well that's not free either so you can't simply ignore it - another 2 or 3 winter months heating cost for my ashp's.

It's optional. I choose not to. Do you have your water heater checked every year?

You need a gas saftey certificate if you're a landlord. But then you don't care what the tenants' heating bill is, so instead of a heat-pump you install cheap oil-filled electric radiators and your tenants pays through the nose for it.

OK I'd mis-Googled the capacity of GCH systems and calculated about 10Kwh for a 40C drop. I'm just trying to figure out why heating using wet rads and a gas boiler is costing so much even with all this A rated stuff. Everyone from these boards to friends to the media are bandying around high heating costs - something I don't suffer from any more.

I should imagine it's pretty expensive for people with resistive electric heating. I don't understand why building regulations still allow new builds to have it installed instead of making heat pumps mandatory.

Mostly though I think people just got too used to cheap energy. Plus modern Britain's pastime seems to be to moan constantly. Especially about whatever the media tells them to moan about this month.

A rated boilers aren't going to have a huge impact just yet. Most of the people on gas still have non-condensing boilers (85%?). I think average boiler efficiency is still not much better than 65%. So a 25% improvement is possible there. And then you can probably reduce ventilation levels as well. People in other countries actually talk about how airtight their house is. This is an alien concept to the British with houses as airtight as colanders. We talk about insulation and double glazing (I could not detect any reduction in gas usage after double glazing), but hardly anyone mentions draughts. A lot of British houses have damp problems too. The usual response seems to be to increase heating and ventilation (!) and assume the root cause is unsolvable.

Britain's housing stock is just abysmally energy inefficient generally. I can't even get my walls cavity insulated. The cavity is too narrow apparently (didn't stop them getting partway through before giving up though).

rothers8080

Hi Rich, it's 14,000 heating, 12,000 cooling I think.

It's 7-9 degrees here today - it's pulling a max of 640w and going down to 90w min - room temp is 24degrees.

Astonishing.

We have just put it up to 26 degrees (now taking 800w- correction, now down to 630w@26degrees) and are lying on the sofa in tshirts and just enjoying it.

Starting the install of the hot water unit this week (if the weather is ok)! Will keep the thread updated with my views on that one too.

richardc1983 wrote: »

My system today in 10hours has cost £2 to heat the flat to 22C.

I usually only have one unit on but one unit uses about 1.2kw per hour to keep the whole flat warm and at 22C setpoint. Total output of the unit is 4kw at a push when on Turbo mode.

@CRAIGX can you tell me what the rated output of your unit is?

Regards
Rich.

richardc1983

OOOH thats very good craigx i dont even get readings that Low and mine isnt one of the cheap units!

Mine is LG Multisplit as I say and with 1 unit running I achieve only about 1100watts when it seems to have slowed down, this is usually when set point is 1C over any more and it shuts off!

They are coming back out to fit remote sensors as when it has been running for longer it seems to slow down but we are thinknig that the airflow (due to being floor mounted) is being sucked back into the unit giving it false temp readings and therefore inverter cannot adjust.

Its 10C here and the unit is still using as much electricity as it would when it is -3 outside but cycling off! HMMMM its annoying me actually as the installer says there is no fault with it! I just feeling fobbed off actually about it all! And cos this guy fitted it as a favour i feel im nagging!

alicelight

Thanks G,

In placing the indoor unit, are any positions optimal, i.e. does a central position matter and should I avoid putting it directly above windows/doors?

richardc1983

You should avoid putting it where the unit will be affected by cooler/warmer air from another room as this may fool the unit into thinking its warmer/cooler than the actual room temp is, so dont place it where you have doors opening all the time, or windows that are draughty.

A lot of manufacturers state not to mount above door ways I know SteveX has his lounge unit above the door way to the lounge but to get a set point that is comfortable he has to increase the set point to say 24C but in actual fact the room temp is about 22C which is comfortable.

This could be to do with mounting above a doorway.

Johnhowell

richardc1983 wrote: »

You should avoid putting it where the unit will be affected by cooler/warmer air from another room as this may fool the unit into thinking its warmer/cooler than the actual room temp is, so dont place it where you have doors opening all the time, or windows that are draughty.

A lot of manufacturers state not to mount above door ways I know SteveX has his lounge unit above the door way to the lounge but to get a set point that is comfortable he has to increase the set point to say 24C but in actual fact the room temp is about 22C which is comfortable.

This could be to do with mounting above a doorway.

Richard,
You say this, but with installing the Heat Pump in a conservatory; the only mounting point would be above the doorway made through the only full height brick wall - the gable end to the bungalow...

Thanks to all for this very informative thread.
John

richardc1983

Yes John that is prob perhaps correct for conservatory however as I say Steve has to compensate his set point. If he wants a setpoint of 22C he has to set it a couple of degrees higher for the room to be this temp.

That could possibly have something to do with it being above a doorway.