@kenian,

hello and welcome to the forum.

Do you know how many kWh your ASHP is using?  Do your numbers mean your heating and HW is £175/month?  Can you clarify which month this is for and what the per kWh rate is?    

The reason I ask is that it's useful to get an idea of what you're using now before suggesting any changes. 

Kev

@kev-m Hi, Heating and hot water is working out at about £175 per month. Our previous bill of £125 was for electric only including the hot tub and all electric in the house. Kw/h  cost is with eon next and is 21p per unit.  Reading is for 71 days taken between the 30th of sept and the 10th of December, utilisation during this period was 2976 units.

I’d a;so like to be able to monitor costs effectively via the system so any suggestions welcome.

Posted by: @kenian

@kev-m Hi, Heating and hot water is working out at about £175 per month. Our previous bill of £125 was for electric only including the hot tub and all electric in the house. Kw/h  cost is with eon next and is 21p per unit.  Reading is for 71 days taken between the 30th of sept and the 10th of December, utilisation during this period was 2976 units.

 

What size is your hot tub? How many litres of water does it hold? Where is it located? What is the temperature setting? How often do you have it switched on?

What size is your conservatory? What is the calculated heat loss? What is the size and type of the heat emitters?

@derek-m we’ve had the hot tub for years so it’s always been part of the electricity we paid before with a bill of 125. We offset it with solar so I don’t believe the hot tub is a factor. Hot tubs are always switched on amd run at a ready temp of 38.5 but as I say it’s been a part of our bill for years.

our conservatory is 15ft by 35ft. It’s part brick but has an insulated solid roof with tiles. Heat emitters are all new radiators *6. 1800 by 450.

Posted by: @kenian

@derek-m we’ve had the hot tub for years so it’s always been part of the electricity we paid before with a bill of 125. We offset it with solar so I don’t believe the hot tub is a factor. Hot tubs are always switched on amd run at a ready temp of 38.5 but as I say it’s been a part of our bill for years.

our conservatory is 15ft by 35ft. It’s part brick but has an insulated solid roof with tiles. Heat emitters are all new radiators *6. 1800 by 450.

 

What period was covered by the £125 bill and what was the tariff? How many kWh's were used? How much oil were you using?

Is the 48m2 conservatory included in the 209m2 floor area?

The six 1800mm x 450mm radiators, have a possible combined output of 13.8kW at a Delta T of 50C.

You did not say where the hot tub is located? Is it inside or out?

@derek-m £125 was our monthly direct debit that always left us with money in reserve. Average actual bill per month over the previous 12 months was £95 per month. Tariff was 16p per unit.  Winter bills could get as high as £110 per month.  The hot tub is outside next to the house. The lady who did the epc measured the conservatory so I assume the 48m2 was in the 209m2. 
hot water is set at 50, heating is set at 45 as I understand it from the paperwork left by the installers.

oil used in a year averaged £450 per year but we didn’t have rads in the conservatory and used bio ethanol in a fire instead at an average of 1 bottle per night in winter , costing £2.

Hi @kenian 

It is better working in kWh rather than monetary terms, since tariffs change, but kWh's don't. The tariff change from 16p to 21p will have increased your bill by 31%, before the addition of your ASHP and six extra radiators.

If your heating is set at 45C, which I assume is the water flow temperature, then it would appear that your system is not operating on weather compensation, but on a fixed water flow temperature. To try to improve the efficiency of your system you should change to weather compensation. You can read back in previous messages or ask Kev, who is the expert on setting the weather compensation on FTC controllers.

Once the weather compensation curve is correctly adjusted, you will need to increase the thermostat on the landing, but leave the one in the conservatory at its present settings. 

I'm afraid heating a large conservatory in Winter is going to be costly, so you must expect higher bills.

@derek-m the weather compensation curve is definitely operable and I agree, I expected the increase with all recent bills but going from paying very little to £300  a month seems excessive to me.

is it true that’s it better to leave temps set as their highs and lows or is it more cost effective to simply turn the heating off overnight in the conservatory which is in fact our main living room

Posted by: @kenian

@derek-m the weather compensation curve is definitely operable and I agree, I expected the increase with all recent bills but going from paying very little to £300  a month seems excessive to me.

is it true that’s it better to leave temps set as their highs and lows or is it more cost effective to simply turn the heating off overnight in the conservatory which is in fact our main living room

Hi Kenian,

If you are operating on weather compensation, then where is the 45C value coming from? Could you post a photo of your controller?

Do you have the heat loss calculations, particularly the ones for your conservatory? If the system designer decided that the conservatory requires six 2.3kW radiators, then the calculated heat loss must be quite high.