How bad is it?

[ToughButterCup]

On 02/02/2024 at 14:04, tw18 said:

...

What am I surprised by is that in the heating season it will chew through an eye watering 100kw pd, I’ve even seen it do over 120 when it is close to 0 degrees outside.

...

 

Could I ask whether you have had your meter checked? When was it last calibrated?

[tw18]

20 minutes ago, ToughButterCup said:

Could I ask whether you have had your meter checked? When was it last calibrated?

 

Haven't had it checked. But the daily readings from the supplier are close to what I get from my own monitor so I have never felt to call them into question.

[JamesP]

On 04/02/2024 at 19:50, tw18 said:

So you're saying its bad, like 4 times worse that yours, but what would a passive house be, 2/3 times better than average?

A lot of people will comment on the accuracy of an EPC however,

The paragraph below is from my EPC, I built my own interpretation of a passive house spec, heaps of insulation, air tight, MVHR blah etc. 

Current primary energy use per square metre of floor area: 35 kWh/m² per year according to EPC.

 

One of the biggest contributors to global warming is carbon dioxide. The energy we use for heating, lighting and

power in homes produces over a quarter of the UK’s carbon dioxide emissions.

The average household causes about 6 tonnes of carbon dioxide every year. Based on this assessment, your home

currently produces approximately 1.4 tonnes of carbon dioxide every year. You could reduce emissions by switching

to renewable energy sources.

[SteamyTea]

48 minutes ago, JamesP said:

You could reduce emissions by switching

to renewable energy sources.

Not always.

It is hard to calculate as it is marginal generation that counts.

So if you swap your FF energy supply to a finite RE supply, the difference is made up by either someone else swapping to FF or extra marginal FF generation.

 

In reality, as we are heading to a low CO₂ generation system, electrification is the best way forward, as well as energy reduction.

[tw18]

So the boiler has been off for 2 hours, with no heating on and just the circulation pump running. No-one is at home so no water has been used, but here is the temp drop from the cylinder.



In 2 hours, is that normal?

[ProDave]

9 minutes ago, tw18 said:

So the boiler has been off for 2 hours, with no heating on and just the circulation pump running. No-one is at home so no water has been used, but here is the temp drop from the cylinder.



In 2 hours, is that normal?

Which circulation pump?  Do you mean hot water circulation, a system used where you have long pipe runs to the taps to give quick delivery of hot water.

 

If that is what is running 24/7 then rewire it ideally triggered by motion sensors in the bathrooms etc so it only comes on when there is actually someone there that might want hot water.

 

The rest of the time it is just sucking heat out of your hot water tank.

[Roger440]

Late into this one. But, yes, seems very high!

 

Ive got a stone built cottage, with 70's extension and even worse 70's double glazing. In wales, halfway up a hill. ?So much colder overall.

 

Im doing circa 70kWh. Fortunately im on oil so only paying 1/4 of the price per kWh that you are.

 

As others have said, id be looking to reduce heat loss first. I would imagine with heat loss that bad theres going to be some easy wins there, especially with air leaks.

 

[SteamyTea]

6 minutes ago, Roger440 said:

Im doing circa 70kWh

I get upset if I use over 20 kWh/day.

[JamesP]

Winter months we use about 15 kWh / day and daily average annually is 7.5kWh / day for both heating and DHW.

13 minutes ago, SteamyTea said:

I get upset if I use over 20 kWh/day.

 

[Roger440]

59 minutes ago, SteamyTea said:

I get upset if I use over 20 kWh/day.

 

Fortunately i dont, as i expected it. Its certainly not a surprise its high. Wasnt using much less in the last place, though that was nearly twice the size.

 

Would be nice to be lower, but back to that payback issue. Just makes no sense. And im releatively confident the government will pay eventually, so no good spending my money.

 

However, there are things i will do, because it will make it nicer, primarily the windows, and the (uninsulated) flat roofed part, which will need reroofing at some point.

 

 

[Roger440]

50 minutes ago, JamesP said:

Winter months we use about 15 kWh / day and daily average annually is 7.5kWh / day for both heating and DHW.

 

 

That would be nice. Not sure if thats achievable in my case without demolition.

[tw18]

4 hours ago, ProDave said:

Which circulation pump?  Do you mean hot water circulation, a system used where you have long pipe runs to the taps to give quick delivery of hot water.

 

If that is what is running 24/7 then rewire it ideally triggered by motion sensors in the bathrooms etc so it only comes on when there is actually someone there that might want hot water.

 

The rest of the time it is just sucking heat out of your hot water tank.

 

Yes for hot water circulation. It is on a timer 0700 - 2230, if you have shower outside those times it's cold period, no just waiting a couple of mins, you can stand it in for 15 mins and it won't get any warmer. Consequently I get shouted at if it gets turned off. 

[ProDave]

3 minutes ago, tw18 said:

 

Yes for hot water circulation. It is on a timer 0700 - 2230, if you have shower outside those times it's cold period, no just waiting a couple of mins, you can stand it in for 15 mins and it won't get any warmer. Consequently I get shouted at if it gets turned off. 

Perhaps one of the other members with a recirculating hot water system can comment.  I can see no reason it should stop delivering hot water if the pump is not running, it will of course take longer for the water to reach the tap.

[SteamyTea]

Is it take water from the base of the cylinder and returning it to the top?

You have a greater temperature drop, over time, at the cylinder base.

Can you check the flow direction?

[Adsibob]

44 minutes ago, ProDave said:

Perhaps one of the other members with a recirculating hot water system can comment.  I can see no reason it should stop delivering hot water if the pump is not running, it will of course take longer for the water to reach the tap.

@tw18 I highly recommend you install:

1) a Shelley smart plug (or if you pump is wired directly into the mains with a fused spur) a Shelley Plus1PM on the cable powering the pump); and

2) a Shelley motion sensor in each place you want to trigger the pump - we have three, one above the kitchen sink and downstairs loo sink and one underneath the vanity unit in our website bathroom.
 

 You connect them to your WiFi and then you configure them via the web portal to switch the pump on for 60 seconds each time the PIR is triggered.

 

It took a day or so of trying different sensitivity settings on the motion sensors before it was working really well. Saves us energy and heat loss but still gives us instant hot water.

 

 In response to @ProDave’s question, all of your HW taps will still work even when the pump isn’t triggered, they will just take longer. So if that bothers you, just add more sensors, but at £75 a pop, three was the right balance for us between practicality and budget.

Edited February 7 by Adsibob

[TonyT]

Is the hot water return just cooling the cylinder if it’s on for 13.5 hours?

 You are pumping hot water around a loop of pipe most of the day, cooling the cylinder as it goes, 

[TonyT]

Can you get a heat loss calculation done for your house say the heat engineer app, costs a tenner  to see what the build is like?

 

what about hiring a thermal camera to help ‘see’ poor insulation/ poor build details?

check UFH is functioning properly?

[marshian]

On 07/02/2024 at 18:59, JamesP said:

Winter months we use about 15 kWh / day and daily average annually is 7.5kWh / day for both heating and DHW.

 

On 07/02/2024 at 18:45, SteamyTea said:

I get upset if I use over 20 kWh/day.

 

Good lord!!!

 

My average over last 12 mths is 22.1 (For both CH and DHW)

 

Summer is 3.5 kWh per day (just DHW)

Heating Seasons it's between 17 & 50 but that hides the impact of a really cold spell

 

Peak daily for 2022 was 90.9

Peak daily for 2023 was 85.1

Peak Daily for 2024 is 81.6

 

So I think I can say even my peak usage is improving

[marshian]

On 07/02/2024 at 22:02, TonyT said:

Can you get a heat loss calculation done for your house say the heat engineer app, costs a tenner  to see what the build is like?

 

I agree - I've done the heat engineer heat loss calculation - as long as can set aside a bit of time to measure wall dimensions and window apertures, have a good knowledge of the fabric of your house (Floors, Walls, Ceilings and Windows) it can give very accurate assessment of overall house heat loss at -2

 

The only thing I think it overstates is the ACH element - some of the default values for ACH is frankly unrepresentative of even 80's housing stock that has had elements of the building upgraded

[Adsibob]

On 07/02/2024 at 21:21, TonyT said:

Is the hot water return just cooling the cylinder if it’s on for 13.5 hours?

 You are pumping hot water around a loop of pipe most of the day, cooling the cylinder as it goes, 

correct. That's why it's worth investing in a PIR activated pump.  Our pump has come on today, for example, 14 times. Each time it comes on it is set to turn off 36 seconds later. So it's been on for about 8 minutes total today. On a busier day of the week it might be 2 or 3 times that.