hmmmmmm room temperature

maxmycardagain

once upto temperature does it cost less to maintain it 18 degrees than at 20 degrees?....(gas heating/radiators)

MattMattMattUK

maxmycardagain said:

once upto temperature does it cost less to maintain it 18 degrees than at 20 degrees?....(gas heating/radiators)

Yes, as thermal losses to the outside world will be lower from a body at 18c than at 20c.

BUFF

in theory, yes. The higher the differential between the external temp & room temp the higher the heat loss.

Mstty

This all comes down to getting to know your house and recording data of energy used, weather for that day etc etc.

We are getting there and for us maintaining 19oC over 18oC costs an extra draw of 2kwh (5kwh output into the house ASHP) per day to maintain that extra degree and 3kwh (7.5kwh) for maintaining 20oC. That's based on an average of 0oC over a 24 hour period. Not exact science in any way but so far the figures are good within 10%.

However that is for our particular house, in its particular area of the UK and the accompanying weather and environmental that go with that as well as hundreds more variables.

So to put this in cost terms a 2 degree raise from 18oC-20oC on average with the outside average daily temperature of 0oc at the current EPG rates for electricity would cost and extra £1.70 a day (5kwh). If we had gas and presuming the boiler was 95% efficient that would cost £1.35 (13.125kwh). obviously this is only applicable to days when the outside temperature and solar gain does not raise the internal temp of the house to 20oC.

EssexHebridean

It’s worth underlining also that ASHPs are going to be more efficient at increasing the internal temperature than GCH or former standard forms of electric heating where you’d presumably need 5kW input to get that same 1° increase? 

macman

The axim used to be that a 1C drop in the set temp will reduce your energy usage for heating by 10%. But whether you'd save 20% by dropping from 20C to 18C depends on so many other factors, not least in the level of insulation in the property.

markin

A google found 3% per c, so is that where the 21c to 18c turned in to every 1c is 10% ?

A news story i read said you only get 10% for the first 1c and then its lower, without giving the starting temp.


EDIT:

It seem the Energy Saving Trust do say 10% but no Data to back that up.

Energy Saving Trust’s top five tips to help reduce energy bills and carbon emissions are:

1. If you turn down your main thermostat by 1 degree, you can save around 10% on your energy bill. If everyone in Great Britain turned their thermostat down by 1 degree, we would reduce energy bills by £670 million, while saving 3.5 million tonnes of carbon dioxide (CO2) per year. However, do make sure your home is warm enough during cold weather to ensure you don’t damage your health. The ideal temperature range to set your thermostat is 18-21 degrees.

The EU say ..  7%

Turning down the thermostat in your home by just 1 °C would save around 7% of the energy you use for heating.

https://energy.ec.europa.eu/topics/markets-and-consumers/action-and-measures-energy-prices/playing-my-part_en

maxmycardagain

Just on 1st thoughts... raising from 18 to 20 will cost, lowering from 20 to 18 saves....... nothing?, surely its KEEPING it at 18 we consider lol (the only cooling process that costs if aircon?) but ...

i can see heat losses may be higher at 20 (theres more to lose) but 14% i cant see

I ask as today i walked our dog, damn cold, i noticed our 1950s bungalow roof was covered in ice, the 900K new builds around the corner had very little on the roofs...as sign of heat loss?

 

Spoonie_Turtle

maxmycardagain said:

I ask as today i walked our dog, damn cold, i noticed our 1950s bungalow roof was covered in ice, the 900K new builds around the corner had very little on the roofs...as sign of heat loss?

 

Not necessarily, if other rooves in a similar position didn't get frost.  It's if you have a row of houses that you can tell the ones in the middle losing heat if they're clear and the ones around them still have frost.

[Some of the houses in our village have clear areas around the chimney with the rest of their roof still frosty, that's a sure sign!]

jvjack

The 900k houses may be being heated to 23 degrees in every room night and day so it might be enough to warm up the roofs more than if at 18 degrees.

markin

New tiles with coatings may simply clear quicker, its frost getting deep into tiles that destroy them.