Taking hours to heat the house

grn99

[Deleted User] said:

In my experience that gave red hot radiators but not much heat in the room.

I agree with your comment about the need for radiator balancing; however, if a 'red hot' radiator is not heating up a room then it means that the heat loss from the room exceeds the heat gain from the radiator. Either the room is poorly insulated or the radiator is under-sized for the room that it is in.

Very true. What I meant was heating it up effectively through balancing and flow rather than it not heating it up at all - in which case as you rightly say, factors such as rad sizing, insulation and associated heat losses equalling or exceeding the heat input.

Chrysalis

BBC discussion comparing heaters here.

They talk about the pros and cons of high peak wattage vs lower peak wattage.

https://www.bbc.co.uk/sounds/play/m001dxtx#xtor=CS8-1000-[Promo_Box]-[News_Promo]-[News_Promo]-[PS_SOUNDS~N~m001dxtx~P_SlicedBreadPortableHeaters_SEG_PNC]

Around 21-22 mins a lady speaks, saying CH is cheaper purely based on the KwH cost, so another person guilty just looking at KwH and making assumptions based on that.

Chrysalis

ariarnia said:

Chrysalis said:

So using smart meter data, I had water heating on for about 2 hours on Friday, sarahs mode says it is 15.6 KwH (central heating would be at least that, my boiler if I have CH on I have to also still heat water). 

15.6 (11.9) x 10.24p = £1.21

2000 watt heater on for 2 hours, and we will assume worst case scenario its on constantly not thermostat controlled.

4 x 33.02p = £1.32

maths look ok to you?

Thats best case gas against worst case electric.

--edit recalculated taking of normal pilot light daily usage.

Depressing figures, just 2 hours of heating per day over £30 extra per month on bill, the problem is if you start at 1-2 hours, it makes the unheated hours so much more difficult as body adjusts to the heated temperatures, so 2 hours quickly becomes 8 hours.  Reality is though the electric heater would be lower then that cost as thermostat would cycle the power.

(not for the op. just talking about relative heating costs)
 
i think that misses that the first couple of hours of gas are the most expensive. which that and the heat loss problem is why a low level of constant heat is said to be more efficient.

because the gas central heating also cycles using the thermostat and a wireless thermostat in the room with you should mean the gas central heating is only on to give the same amount of heat as the electric but using a cheaper fuel. 

we pay 3.5p for gas and 20p for electric (on a fix till march).

heating the hole house to 15 degrees all day (on a thermostat) 'cost' us 20kWh per day last month. then we could have 3 or 4 hours of logs on the stove heating it and the surrounding rooms to 20 in the evening vs needing to light the fire as soon as one of us gets up and keeping it going all day.

3.5*20 is 70p (for 24 hour background heat)
20*16 (8 hours of a 2kwh electric heater) is £3.20

at cap rates it would be 
10.3*20 = £2.06 (24 hours of 'not cold')
34*16 = £5.44 (8 hours of 'hot')

for full comparison we've worked out that we burn about 3kg of logs in an evening if we keep it going from dinner to bed time. that's about (very roughly) 15kwh of heat so about the equivalent of a 3kw electric heater. we can't price the logs as its a mix of free, bought ready to burn and bought cheap to self season for a couple of years. 

and we've spent time and money over the last few years sealing all the cracks and putting up thick curtains over all the doors and windows (door curtains do make a real difference) to make sure the space were heating are as insulated as possible without serious diy (which we'll be doing as and when now we bought the place from the landlord). 

As I said everyone has different situations, different insulation, and different efficiency boilers.

I do agree that older gas pricing was more favourable in the past than it is now vs electric costs, during the energy crisis gas costs have gone up more than electric, but I think it is reasonable to use current EPG rates for my maths.

For my boiler, my CH which has no thermostat, my poor insulation, I think I would need gas KwH price at absolute most of 20% of the electric cost.  Currently gas is at about 33% cost.

It was interesting to do the maths.  I do think in my case portable heating is the better choice, whilst for you it looks like CH is the clear winner.

--edit

Someone elsewhere has reported from smart meter 7 hours of CH used up 84 KwH.

7 hours of a 2000 watt heater on no thermostat control would be 14 KwH.  So for costs to be favourable in that instance for one room, gas would need to be lower than 16% of electric unit cost.

Gas boilers been banned soon as well in new builds?

Astria

Chrysalis said:

7 hours of a 2000 watt heater on no thermostat control would be 14 KwH.  So for costs to be favourable in that instance for one room, gas would need to be lower than 16% of electric unit cost.

Gas boilers been banned soon as well in new builds?

Don't forget heat pumps, which can still be 200% - 300% more economical than typical resistive based heating even at todays temperatures. I have air conditioning in my other office which can do both heating and cooling, and it's far better at heating the room than a fan heater for example, and uses less electric.

[Deleted User]

Spies Dolor said:

In my experience that gave red hot radiators but not much heat in the room.

I agree with your comment about the need for radiator balancing; however, if a 'red hot' radiator is not heating up a room then it means that the heat loss from the room exceeds the heat gain from the radiator. Either the room is poorly insulated or the radiator is under-sized for the room that it is in.

My living room takes 1 hour per 1c (high ceiling) 

We are using 40-50kwh of gas a day at 10.3p/unit 

But for how many hours is that? Yes £5 a day £7 true price!!

Spies

I let my house cool down to 9.5c the other day, it took an entire day and £11 to get it back to normal.

Today the house has been more comfortable and used £9 of gas. 

Chrysalis

Astria said:

Chrysalis said:

7 hours of a 2000 watt heater on no thermostat control would be 14 KwH.  So for costs to be favourable in that instance for one room, gas would need to be lower than 16% of electric unit cost.

Gas boilers been banned soon as well in new builds?

Don't forget heat pumps, which can still be 200% - 300% more economical than typical resistive based heating even at todays temperatures. I have air conditioning in my other office which can do both heating and cooling, and it's far better at heating the room than a fan heater for example, and uses less electric.

Indeed, with my options, I settled on using an electric blanket, far far better than a fan heater.