Wow Mars😳. We’ve only used 160kWh since 21st April installation date. I think you need to wear a sweater 😊

Hi Mars,

Remember, you also replaced those radiators, so may have been using more energy in those rooms.

I have been making good use of solar gain when available, but also using the A2A ASHP to bump up the indoor temp during the day to 23C to 24C, powering it from our solar PV. This in turn means we use a great deal less gas during the night, in fact the other night we used no gas at all. Even on the cloudy days we have had recently, there was sufficient solar PV to run the heat pump and heat the hot water, though I agree with you, it has been cloudier and colder than May last year.

Looking at the data from my Immersun unit, the total generation for May last year was over 500kWh, whilst almost half way through May this year is showing only 196.8kWh.

We need more of those big fans to blow the clouds away.

Hi Mars,

I have just had a thought, are you still running your system with the water flow temperature set at 45C? If so, you should probably think of reducing it, and see what affect this has on your consumption figures.

I have read your comments about the price of wood. Do you think it grows on trees!!!!

@derek-m, that's a good idea. It's a good time to run that experiment actually. I'll do that today.

As for the wood, yes, it's absolutely crazy what it's selling for at the moment. 

@julianc, that's impressive Julian. I don't know why our heating has been running as much as it has. I should probably drop some of the target temperatures in rooms. I just never realised it was on so much this month.

Hi Mars,

I think someone else has mention it, but I was also going to suggest lowering the temperature setting in the rooms that you do not usually use. Say by 1C.

To get meaningful results though, you should only make one change at a time, and assess the impact of that change, before making any further changes.

Whilst it may take some time to make and assess all the proposed changes, it will pay dividends in the future, since you will know which has the greater impact.

A observation that is probably obvious to some but I had never thought about it.  My house uses significantly more energy to heat it when it's windy.  The last two days have been very windy but no colder than the previous few but we've used about 25% more kWh.  COP has been similar.  As I said, not a surprise when I think about it but how exposed/windy your house is might make quite a difference to your energy consumption. A 'wind chill factor' for houses?

On a sepate note we're getting MMSP installed next Friday 28th May so I'll report back then.  I also need to get on with the RHI application but I want to do all of it together so will do it after Friday. 

@kev-m, that's quite an interesting observation. We've never noticed a drastic difference between when it's windy or calm from a consumption perspective. I'll go through the data from our ASHP and weather station tonight and see if there's a correlation. 

ASHP and wind chill - a whole new topic of conversation 🤣 

Hi Mars,

The 'wind effect' is probably due to several factors, which can be explained by the laws of physics.

1) The outside fabric of the building is warmed by solar energy, particularly direct sunlight. This in turn reduces heat loss, since the temperature difference between the inner wall and the outer wall will be less. Air is actually a poor conductor of heat energy, so on calm days the air in contact with the outer fabric of the building will warm slightly and also reduce the heat loss. On windy days this warm air is continually being replaced with colder air, which in turn has a cooling effect on the outer wall, which in turn increases the overall heat loss of the building.

2) Wind can create a pressure differential between the inside air and that outside. Any holes in the fabric of the building will therefore result in a movement of air either into the building or out from the building. Either will have a cooling effect. Air flow around a bluff object will cause vortices to be created which also cause a difference in pressure between inside and outside.

3) Wind passing over a chimney will create a slight vacuum, which in turn will draw air out of the building and will be replaced by colder air from outside.

If you have a chimney, try placing a candle near it to see if there is appreciable airflow.

Hi Mars,

You will probably find that rain also has a cooling effect, which will also increase heat loss.

Hi Mars,

Did you try any of the suggestions about reducing water flow and/or room temperatures?

If so, what were the results?

Posted by: @derek-m

Hi Mars,

You will probably find that rain also has a cooling effect, which will also increase heat loss.

If the outside walls are wet, when that water turns to vapour, energy will be used; the walls will get colder so the temp difference between inside and out, and therefore the heat loss, will increase.  And more so if it's windy because the water will eveporate faster.  I think ...