Air Source Heat Pumps

paceinternet

stevehead,
Very interesting and look forward to seeing more info like this.

I've not looked back in the thread to see what you are heating with these, but for example, Nov 09:
Total 180kwh (£18 ish), average 6 kwh per day. November was pretty cold around here and we certainly needed heat on most days, and some days needed to be on all day.
How many hours do you think you had the heating on?
It suggests that if the heat pumps were 1kw each, then you only ran them for 3 hours a day.
Do you have some other heating, or a very high level of insulation?
Or what temperature were the up and down kept at?

thanks

richardc1983

With me being off work at the moment with a broken foot I am in the house all day so the heating is on from about 11am to possibly 3am in the morning.

The heat pump is used during this time, we have been averaging about £4 a day for this and this is on a coin meter so we pay more for our electric. £1 of this is for other electric usage such as tvs, fridges, washing machine, dishwasher, lights that sort of thing.

Thats 3 indoor units to 1 outdoor unit, only 2 indoors in operation at any one time though.

stevehead

paceinternet wrote: »

stevehead,
How many hours do you think you had the heating on?
It suggests that if the heat pumps were 1kw each, then you only ran them for 3 hours a day.
Do you have some other heating, or a very high level of insulation?
Or what temperature were the up and down kept at?

thanks

Working from home, I tend to keep the downstairs at 22C all day every day (on at 7.00am), then bump it up a bit at night. Of course if it's sunny, I turn the unit off.
Upstairs is set at 21C and is usually on 7.00am - 9.00am and 4.30pm to 9.00pm.

The heat pumps are of the inverter type, and their power consumption based on load. Mine tend to vary from 320 watts to 440 watts in normal operation.

The only other form of heating I have is from cooking, and the Plasma TV & Stack in the Living Room. It costs more to watch TV than keep warm!

Insulation is good in the loft & walls, pretty poor windows tho'.
Lowest internal temp indoors recorded this winter is 17.5C bathroom.
I know the Scots amongst us will disagree, but living in Plymouth makes a big difference. So far this winter we've had 1 mild frost, and only 4 days when it's fallen below 7C by bedtime.

richardc1983

Are you still using your heat recovery units Steve and are they functioning now temperatures have dipped.

I know you also set your units at 21C upstairs and 22C downstairs but what do the rooms maintain at that the units are not in, obviously I would expect your lounge to be 22C as the lounge has the unit in, but what about your kitchen/diner and hallway?

Also what about the bathroom, and bedrooms what does these maintain at if the unit on the landing is set at 21C?

stevehead

richardc1983 wrote: »

Are you still using your heat recovery units Steve and are they functioning now temperatures have dipped.

I know you also set your units at 21C upstairs and 22C downstairs but what do the rooms maintain at that the units are not in, obviously I would expect your lounge to be 22C as the lounge has the unit in, but what about your kitchen/diner and hallway?

Also what about the bathroom, and bedrooms what does these maintain at if the unit on the landing is set at 21C?

Hi Rich,
Yep - still using the Heat Recovery Units.
The Mitsubishi in the Living Room. Very good. Esp good at removing cooking condensation & smells (open plan kitchen/dining room).
I bought an Infrared (point and pull trigger) Thermometer to help with taking readings. Currently, the Mitsubishi is
Input (Exhaust) Air Temp = 24.4C
Output (Fresh) Air Temp = 22.1C
Outdoor Air Temp = 8.2C

Upstairs, the bathroom unit is fab. By the time I've finished a rub down with the towel after a shower, the air has cleared and I'm left standing in warm comfy air. It's actually got quicker at drying out the bathroom as the outside temp has dropped.
The bedroom unit - well - not so good. Firstly, it's likely too small as it hasn't stopped condensation on my windows. Secondly it's horribly noisy in a storm. It whistles and howls waking you up at night.
The Mitsubishi is far better designed in the respect of noise attenuation, and even has a sliding door to close off the vents completely if needed. The Kair units absolutely need this if they're to be recommended for bedrooms.

The Living, Dining Room & Kitchen always within a degree of each other. The coldest place is the north facing bay window in the Living Room. Draughty there!
Upstairs, I guess the best way to put it is that setting the unit to 21C gets the rooms all to a comfortable temp for the kids to live in. The loft is normally 20 - 22C and relies solely in convection from the floors below.

The objective is to try and replicate the conditions my GSH provided and the ASHP nearly has.
Where it doesn't is
The Hall. This is the coldest part of the house.
The Window Bay. The radiator underneath used to offset the cold from the windows.
I have actually ordered Rationel Triple Glazing to fix this, but that won't appear till spring.

richardc1983

I suppose though Steve the benefit of the ASHP is that it really doesnt affect operating costs to increase the temps downstairs to offset that colder window bay.

When our central heating goes off here, and the heat pump is on whilst I can have a higher room temp setting when it reaches set point you can feel cooler air that is circulating within the room down the cold walls and windows etc.

I solved the window issue by putting the curtains up onto the window sill.

stevehead

richardc1983 wrote: »

I suppose though Steve the benefit of the ASHP is that it really doesnt affect operating costs to increase the temps downstairs to offset that colder window bay.

When our central heating goes off here, and the heat pump is on whilst I can have a higher room temp setting when it reaches set point you can feel cooler air that is circulating within the room down the cold walls and windows etc.

I solved the window issue by putting the curtains up onto the window sill.

Yes it's true the costs will be negligable, but a cold window is a cold window and the downdraft from it is uncomfortable. It's like a cascade of cold air which then runs along the floor. My solution is to not sit there!

richardc1983

Have you tried long curtains that touch the floor or tucking them onto the windowsill?

stevehead

mech wrote: »

....but I think you might be surprised how little difference the Scottish climate is to Plymouth.

Yes Mech, very little difference.... on the Kelvin scale!
Like today at 9am
Edinburgh - 0C
Plymouth - 10C

It's differences in this crucial range that will affect the effective COP of an ASHP system.

Andy_WSM

stevehead wrote: »

Yes Mech, very little difference.... on the Kelvin scale!
Like today at 9am
Edinburgh - 0C
Plymouth - 10C

It's differences in this crucial range that will affect the effective COP of an ASHP system.

Plymouth got up to 10C today?!

We struggled to 3C here in Weston-Super-Nightmare and my heat pump has struggled as a result. It's still maintained the temperature today, but used an extra 5KW/h of power to do so.