Do I need a radiator upgrade?

dr_bogenbroom

Hi,

Sometimes I feel my house can take a while to heat up and not sure if I’d benefit at all from upgrading my radiators? These were installed when the house was built in 1994 and run off 15mm pipe work. 

All are of this style and some are just single panel.

tacpot12

Turning the heating on sooner will be a cheaper solution than changing the radiators. You might also turn up the temperature of the water supplied to the radiators. Does your boiler have weather or load compensation? 

dr_bogenbroom

Ok - our boiler is a 14 year old oil boiler but it is condensing I think. Not the best I know but I’ve read it’s best to wait until it dies before replacing? 

FreeBear

What I usually recommend is measure up the room sizes & window/door areas. Punch the numbers in to this online calculator - https://www.stelrad.com/basic-heat-loss-calculator/ and note the recommended radiator sizes. Play around with the "System Temperature" and compare the numbers at 40°C (flow temp of 60°C) and 30°C (flow temp 50°C).

Measure the size & type of the existing radiators and take a look at https://www.simplifydiy.com/plumbing-and-heating/radiators/power to get an approximate heat output at a flow temperature of 70°C. The two sets of numbers should be fairly close if your heating system had been properly specified at installation time.

If the numbers are close, but rooms are not heating up effectively, it is possible likely that the system needs balancing. In the meantime, increasing the flow temperature will boost the heat output from all the radiators. Try not to go much above 70°C or you will reduce the boiler efficiency by quite a bit.

Side note - 15mm pipes to the radiators is good, but you also need to know what size the main feed & return pipes are. 15mm pipe will carry ~8kW of heat, and 22mm is good for ~18kW (dependent on pump speed and water temperatures).

ThisIsWeird

dr_bogenbroom said:

Hi,Sometimes I feel my house can take a while to heat up and not sure if I’d benefit at all from upgrading my radiators? These were installed when the house was built in 1994 and run off 15mm pipe work. 

All are of this style and some are just single panel.

Hi Dr B.
That example is a double-panel with convector fins, so is pretty much as powerful as it gets for its size. I'm guessing you don't want to go physically larger? 
Q - do they become 'hot'?
How hot - for how many seconds can you keep your hand on them?
How quickly do they become hot when the CH is turned on from 'cold'?
And, could you list all your rads (or your the house plan in the sales particulars), turn on your CH, and run around constantly, touching them all to see if they heat up at roughly the same speed? Are some noticeably faster/hotter than others?

At 14 years old, your boiler will most likely be condensing, yes, and if running ok - which is also likely - not at all worth replacing.
How long have you lived there for? Has it always been the same?
A 1994 house should have a very decent level of insulation, so this is all a bit mysterious.
Make and model of boiler, please, and ditto of your timer and room 'stat.

Lorian

Also what is your flow temperature set to on the boiler?
Bled the radiators?
Made sure they are balanced?

Albermarle

 turn on your CH, and run around constantly, touching them all to see if they heat up at roughly the same speed? Are some noticeably faster/hotter than others?

Make sure all the TRV's are fully open before doing this test. 

ThisIsWeird

Albermarle said:

 turn on your CH, and run around constantly, touching them all to see if they heat up at roughly the same speed? Are some noticeably faster/hotter than others?

Make sure all the TRV's are fully open before doing this test. 

D'oh!

badmemory

Don't forget to feel the bottom of the radiators.

dr_bogenbroom

Do you know what… after all of your feedback it’s likely not the radiators that are the problem. With this bout of wind we’re having over here in NI I’ve noticed a few sources of draughts. There is also a small section of inaccessible roof above our WC and cloakroom that has no insulation and I noticed a draught coming in from the light fittings! I’ve no idea how I’ll insulate here though…

ThisIsWeird

dr_bogenbroom said:

Do you know what… after all of your feedback it’s likely not the radiators that are the problem. With this bout of wind we’re having over here in NI I’ve noticed a few sources of draughts. There is also a small section of inaccessible roof above our WC and cloakroom that has no insulation and I noticed a draught coming in from the light fittings! I’ve no idea how I’ll insulate here though…

Yup, wind affects our 1930s house more than just a low temp too. General draughts, coming up through floorboards, seeping through the carpets, from under skirting boards, stuff like that. You'll notice it coming in from under closed doors from other rooms, for example. 

How do you know that your WC ceiling has no insulation above it?

Tbh, I doubt the issue is from small holes like that, but likely more an overall seepage! Do you have suspended timber floors, for example? Check around the doors to the room using a smoking taper or similar.