How we reduced our heating gas consumption by 25% 6 January 2022 at 1:46PM edited 30 November 2022 at 11:44AM in Green & ethical MoneySaving 42 replies 2.7K views

Screwdriva

2021 vs. 2022 comparison of actual kWh winter heating consumption (will update this thread in March to account for temperature variance). The reduction in consumption is measurable, so wanted to share how we were able to substantially reduce our property's heating gas consumption. Appreciate that not everything will be applicable to all but perhaps some may be useful to some. 

1) Radiator reflectors - Has its share of skeptics lacking actual experience but we've found marked improvements in our comfort levels and increased residual heat levels after the desired temperature has been achieved and the boiler has cut off. All for <£30.

2) Boiler Condensing mode - This was a game changer!. Turning our system boiler temperature control (located on the boiler - not the thermostat setting) to ~52 degrees. This means the return flow temperature will be 30-32 degrees which is low enough to make modern condensing boilers achieve in excess of 92% efficiency. We still achieve the desired room temperature but slower and steadier, without the boiler cutting in and out. In so, the boiler's life is also extended.

3) Electric Space Heating - Used only on the rare clear, sunny winter days when our rooftop solar can compensate for the massive electric draw a space heater requires.

4) Gas Fireplace - Used on non-sunny evenings, our Nu-Flame gas fireplace warms the living area effectively, using ~2/3 less gas than the 18 kW main boiler would. A high efficiency fireplace is essential for this - our open flame unit is rated 77% efficient.  Glass fronted fires can achieve in excess of 90% efficiency.

5) Blinds wide open on Sunny Days - Seems obvious but we remain in awe of how quickly the property heats itselfs via solar radiation. We often switch the boiler off entirely and bask in sunlight, rare as it may be. 

6) Insulation sticky tape - Great for sealing older windows and doors to prevent cold air entry. £2 on Amazon made a massive difference in our leakier rooms and attic door.

7) Geofencing and Smart Thermostats - Another seemingly obvious one till we realized how often we forget to turn down heating when we head out. Another great source of savings for a relatively low cost. 

8) Don't shut the cooking OVEN door/ Don't wash hot utensils till they cool naturally / Leave the kettle lid open - An oven or kettle left wide open allows for heat to transfer into the property. We leave our oven door open with the oven fan running for a few minutes - effectively transforming it into a large space heater - to quickly warm up the floor.

9) Chimney Sheep draft excluder* - £22 allowed us to seal off our chimney from drafts using this well made (in the UK) woolen excluder. No more unwanted cold or hot air coming down our chimney. *New for 2022.

We plan on installing underfloor heating on the ground floor of our townhouse to further increase efficiency while also adding load compensation or weather compensation if possible in 2022, when gas prices are expected to skyrocket. 

December 2020 (Average Temperature 7.2 degrees Celsius. 3764 kWh used over 33 days.)


VS. December 2021 (Average Temperature 8.2 degrees Celsius. 2783 kWh used over 28 days).

2nd_time_buyer

Thanks for the reminder. Just turned my radiator temp down to 55 (from 70). Was meaning to do that for a while

Spies

2nd_time_buyer said:

Thanks for the reminder. Just turned my radiator temp down to 55 (from 70). Was meaning to do that for a while

I do that but when we get into single figures outside, it just never reaches the target temperature in the room!

2nd_time_buyer

I'll see how we get on. I have a few radiators turned off which I can reinstate. I'll have to increase the amount of on-time on the timer.

Since COVID I have been working at home in the loft. I have just got an AEG portable air-con with heat pump, that I have up here. It consumes around 700w and outputs 2.2 kw of heat.

... those figures are a bit miss-leading as it is sucking up the air from downstairs (and ultimately outside). But it basically means that I can have the heating in the house turned off all day. Even today when it has not got much above freezing outside it has on average only consumed 300 w throughout the day and it is 21-22 degrees up here. Most of which is covered by the solar panels (well maybe not today - there is a pea souper outside).

theoretica

Spies said:

2nd_time_buyer said:

Thanks for the reminder. Just turned my radiator temp down to 55 (from 70). Was meaning to do that for a while

I do that but when we get into single figures outside, it just never reaches the target temperature in the room!

Likewise - I need to change the temperature twice a year and am contemplating some larger radiators.

Screwdriva

2nd_time_buyer said:

Since COVID I have been working at home in the loft. I have just got an AEG portable air-con with heat pump, that I have up here. It consumes around 700w and outputs 2.2 kw of heat.

Would you mind sharing a link to that portable AC? We recently acquired a DeLonghi Pinguino PACEX 100, which consumes 600W and appeared to be the most efficient non-Chinese brand portable available in the UK. 

Spies said:

2nd_time_buyer said:

Thanks for the reminder. Just turned my radiator temp down to 55 (from 70). Was meaning to do that for a while

I do that but when we get into single figures outside, it just never reaches the target temperature in the room!

It takes us a few hours but it does eventually hit the desired temperature. As long as your radiator return flow temperature is under 35 degrees, you're achieving a near optimal condensing effect. 

2nd_time_buyer

Screwdriva said:

2nd_time_buyer said:

Since COVID I have been working at home in the loft. I have just got an AEG portable air-con with heat pump, that I have up here. It consumes around 700w and outputs 2.2 kw of heat.

Would you mind sharing a link to that portable AC? We recently acquired a DeLonghi Pinguino PACEX 100, which consumes 600W and appeared to be the most efficient non-Chinese brand portable available in the UK. 

Spies said:

2nd_time_buyer said:

Thanks for the reminder. Just turned my radiator temp down to 55 (from 70). Was meaning to do that for a while

I do that but when we get into single figures outside, it just never reaches the target temperature in the room!

It takes us a few hours but it does eventually hit the desired temperature. As long as your radiator return flow temperature is under 35 degrees, you're achieving a near optimal condensing effect. 

It is this one:

https://www.aeg.co.uk/vacuums-home-comfort/air-comfort/air-conditioners/portable-air-conditioner/axp26u558hw/

I paid £180 on Facebook Marketplace. AO might have some reconditioned units on their Ebay outlet.

Few things to note:

- This 9000 BTU model has the lowest power, highest efficiency, and lowest noise (not only compared to the other AEG offerings but compared to anything else I could find on the UK market.)
- The HW at the end of the product name means it has heating (don't confuse it for the CW models).
- I have used insulated ducting to improve efficiency (maintain the vent pipe temperature).
- The ducting is ported straight out through a soffit (rather than through a window, which also helps) 
- The condensate pipe also goes out through the soffit (aimed away from the wall). It is not needed for cooling but in heating mode, a fair bit of water is extracted (several litres a day).
- There is potential to increase the efficiency further by converting it to a dual hose e.g. https://www.thingiverse.com/thing:4519681
- Don't confuse sound power with sound pressure when comparing units. Sound power is the amount of sound energy produced by the unit. Sound pressure is the noise level at some distance from the unit, which also depends on the environmental conditions. Often the distance is not stipulated, so it is more reliable to compare sound power levels, which are typically in the region of 60-70 dBA for air conditioners. 

Edit: I looked at the DeLonghi Pinguino units. They look pretty good, as I recall they didn't have heat-pump mode and were a bit louder. I have measured the AEG unit with a Sound Level Meter (I am an acoustics Consultant) and can confirm the levels are accurate. If anything they are an overestimate, as these are the highest levels and most of the time it is quieter, once it is in its stride.    

Screwdriva

Edit: I looked at the DeLonghi Pinguino units. They look pretty good, as I recall they didn't have heat-pump mode and were a bit louder. I have measured the AEG unit with a Sound Level Meter (I am an acoustics Consultant) and can confirm the levels are accurate. If anything they are an overestimate, as these are the highest levels and most of the time it is quieter, once it is in its stride.    

I can confirm no heating on the PAX EX100. At the time, I couldn't find anything more efficient or quieter myself but your Google Fu may exceed my own. It is rated at 10000 BTUs which is what impressed me.

2nd_time_buyer

Screwdriva said:

Edit: I looked at the DeLonghi Pinguino units. They look pretty good, as I recall they didn't have heat-pump mode and were a bit louder. I have measured the AEG unit with a Sound Level Meter (I am an acoustics Consultant) and can confirm the levels are accurate. If anything they are an overestimate, as these are the highest levels and most of the time it is quieter, once it is in its stride.    

I can confirm no heating on the PAX EX100. At the time, I couldn't find anything more efficient or quieter myself but your Google Fu may exceed my own. It is rated at 10000 BTUs which is what impressed me.

The efficiency of that unit is very impressive for AC. The low power input matches solar very well.

The standard for measuring the efficiency of portable ACs is a joke and is currently up for revision. For single hose units it neglects two big things:
- Heat radiated from the hose
- Hot air being drawn into the house

The revised America standard addresses these, and units over there are often quoted with two BTU values. The lower value (DOE), takes into account these factors, so that they are more directly comparable to a split unit ACs. Typically these values are between 50% and 75% of the BTU value that we use.

In heat pump mode, single-hose units are even more inefficient, as the differential between the inside and outside temperature being drawn is even greater. In fact they can sometimes run at a negative efficiency. In my case, it works, as I am happy to suck the heat from the rest of the unused house during the day which can then be reheated with gas in the evening. 

ispookie666

This is really good.  
I presume you have a combi boiler?  

2nd_time_buyer

Thank you. I went full nerd on it.

Yes, we have a combi boiler but no radiators in the loft.