realistic underfloor heating costs

[Boxerman]

I'm thinking of installing electric underfloor heating in a soon to be built conservatory which will have laminate flooring. Now I know how to calculate running costs based on theoretical usage i.e. the internal size is 12m2 and the mat will be 130watt/m2. So @ 10p per kw/h it'll be £3.77/day however I'm presuming/hoping that it wont be drawing this much power constantly as it'll be set mostly to lowish background heat throughout the daytime whilst we're out at work.

Anyone any experience of rough running costs on a similar system based on actual bills?

 

[ricicle]

If you have to go for dry UFH make sure the floor is well insulated below.
I find that the UFH will not heat the conservatory much but will allow the kids to be able to play out on the tiled floor
Friends of ours without UFH say that their conservatory is virtually a no go area in the winter for the kids because the floor is so cold.

 

[davy_owen_88]

As ricicle has said, 130w/m will not be sufficient for anything more than floorwarming in a conservatory. They do offer higher rating (I think it's closer to 300w/m) specifically for rooms with high heat-loss so that might be worth considering if you don't want to have panelheaters/radiators etc.

Also the energy usage calculation will depend on whether you are going for the heating cable buried in screed or the thin heating film placed directly under the laminate. The cables have to heat up the entire slab so will need to be on for longer before you notice the warmth. If you are using the heating film then you can add extra insulation underneath and because it is in contact with the laminate you will feel the heat far quicker.

Make sure you spend as much as you can afford getting the lowest heat loss for your conservatory - high spec glass and plenty of underslab insulation to reduce your energy usage and make the ufh atleast somewhat effective.

Also are you sure 10p/unit is accurate for your electricity tariff? With the recent increases mine has gone up to closer to 14p, and that 4p will add up over the year.

 

[Boxerman]

It'll be a suspended floor and I'll insulate between that and any heating element. Looking at 150w ribbon or carbon mats which apparently have a very quick warm-up time

 

[breezer]

my 2p worth

heating mat is in the floor, it breaks down, you are stuffed.



whats wrong with a water radiator on a Ch system, it gives up, get a new one

 

[jj4091]

my 2p worth

heating mat is in the floor, it breaks down, you are stuffed.

Not so bad with click-lok laminate flooring

 

[breezer]

maybe bu the Op has not mentioned that, perhaps he will now

 

[Boxerman]

actually I was looking at the click-lok type flooring so replacing is an option if i use electric rather than wet underfloor.

On the advice re: the standard rad I've been advised that you are no longer able to fit one in a conservatory

 

[^woody^]

On the advice re: the standard rad I've been advised that you are no longer able to fit one in a conservatory

The requirement is that the heater/heating system can be isolated from
the rest of the dwelling.

eg a radiator with a thermostatic (or other) valve

 

[Richard C]

On the advice re: the standard rad I've been advised that you are no longer able to fit one in a conservatory

On the advice re: the standard rad I've been advised that you are no longer able to fit one in a conservatory

The requirement is that the heater/heating system can be isolated from
the rest of the dwelling.

eg a radiator with a thermostatic (or other) valve

Spot on from Woody & don’t forget the external door betwixt the two. If you decide to go for U/floor, don’t believe the salesman if they tell you less than a factor of 1.8kw/m. This will give you adequate capacity; heater mats are relatively cheap & you only get charged for wot you burn! But remember a cons. is really not very heat efficient & whatever heat source you chose, on bad days & evenings this time of year it aint gonna be cheap to ru; especially these days! We have the best you can get as far as u/floor insulation, heating, glass & a high spec roof etc. but, apart from sunny day lunches, we’ve now abandoned our cons till spring! Don’t believe all you’re told or you will be seriously disappointed & be sure to work out the math! If you want all year round usage, you may be better opting for a garden room.

 

[big-all]

ok my thrupence worth

heating any room is always cheaper with gas [excluding economy 7]

a kw off gas is around 4or 5p half the cost off electric

heating mats are usless in the colder winter months if you have high loss areas like consevatorys

if you are loosing say 3kw of heat an hour at say 21 degrees 1 kw will only increase the temperatute to around 5 or 6 degrees 2kw to around 11 or 12
3 kw to around 17 or 18deg and 5 or six kw to raise the level up to 21deg in 40 mins then 3kw to maintain at that level

so in other words underfloor no good for keeping conservatorys warm if the outside temperature is frosty they may keep the chill off at around 7 drgrees or so but not much more

 

[Boxerman]

Looks like a radiator it is then, i'm on oil fired heating so hopefully prices wont go through the roof again although long term I guess they'll have to. May look at underfloor as a back-up heat to torn on only when required.

 

[Richard C]

Looks like a radiator it is then, i'm on oil fired heating so hopefully prices wont go through the roof again although long term I guess they'll have to. May look at underfloor as a back-up heat to torn on only when required.

If the cost of the installation of U/floor is not an issue you may as well have it as not, you won’t get a second chance. Ours will keep the cons. perfectly comfortable in spring & autumn but once the outside temperature drops below 10 degrees it starts to get expensive & when it’s really cold outside you can literally feel the cold air falling off the windows onto you; your feet & legs still stay nice & warm though! I was also going to fit a radiator spur off the main system (with isolation & temperature controls) but at around 70 cu/m it would need one mother of a radiator to keep up.