Heating System advice please!!

Comic Book Guy

Hi All,

Started our build last week.
The heating system we proposed was a condensing boiler running underfloor heating on the ground floor and radiators upstairs. We are also going with solar panels and a small stove in our vaulted sun room that was going to act as a back up in case anything went wrong with the boiler.
Was talking to ourplumber this morning who put in a similar system and adviced that we change it to either underfloor heating on both floors or radiators only on both floors.
What do people think? Would prefer to go with the underfloor all over saving the space rads would take up etc. However one of the reasons we decided against underfloor upstairs initially was that a couple of mates that got it done reckoned the bedrooms could get stuffy.

Some advice please would be great.

Heading out the door now to head up to the match in Aviva so wont get to read replies til the morning so thanking you in advance!

bbam

When we were researching our build I spoke with two folks who had underfloor heating runing from oil boilers, they both were unhappy with the economics of it overall, we opted for rads all round...

Solar panels are a good addition for hot water but don't expect any calculated pay-back time..

We have a stove with backboiler in addition to the oil, very happy indeed...

imitation

Ì dont think the nature of ufh is unsuitable for a bedroom really, its designed to keep a room at a certain temperature for a long duration, in a bedroom most people like it cool at night with a bit of top up heat before bed time and after you get up.

Im not certain why he said go with all one or the other, I know of a few people who went with ground floor UFH & 1st floor rads. I guess the main problem is you need low temperature rads for upstairs which may not pump out as much heat.

LoTwan

The issue I came across was the opposite but may still be relavent. We are going with an Air to Water system so low temperature and as a result were faced with having fan assisted low temp rads upstairs which were proving to be as expensive as putting under floor heating in there.

From my understanding a condensing oil boiler would raise the overall temperature of the system higher then the UFH needs so you would have to actively cool the water in the heating system and then need low temp rads upstairs which raises the cost of the system two fold... so I get the logic of either have rads up and down or UFH up and down.

If you go with UFH is there an option to have each bedroom as an individual zone thereby increasing the control you have over the temperature of the room?

sinnerboy

Rads distribute a little water at high temperature pumped quickly through . A condensing boiler is suited to these "quick bursts" of energy which most of us who grew up in Ireland expect from a heating system . Heat pumps cannot perform like this - economically .

UFH distributes a lot of water at low temperatures pumped slowly through . Heat pumps are more suited to harvesting heat for this task - slow and gradual collection and distribution of heat is the ONLY way a heat pump has any chance of not ruining it's owner in fuel bills . Many - by no means all - Irish people find out too late they don't like the lack of "responsiveness" of UFH .

You can mix UFH + Rads . You must only use a boiler not a Heat Pump .
The high temp water is fed directly to the rads as usual i.e. like in a rads-only system . The water from the boiler to the UFH is mixed with cold water via a manifold to reduce the temperature down . Each room should be fitted with it's own stat - a sort of zoning .


BUT

You should not be starting works with such questions not answered . At the very least you should have DEAP calcs to
1. inform you of both your annual heat demand together with the required heat load ( boiler size ) .
2. How you may comply with your renewable energy obligations
3. Very much not least - how you may comply with Part L

If you do this you will find that sorting your building fabric well will in fact make the provision of a heating system very simple .

Go for Passiv - you may even eliminate the need for one . At all .

Comic Book Guy

Thanks for the replies lads, much obliged.

Certainly a lot to mull over for next few days before i make up my mind one way or the other.

The best way to feed a UFH system from an oil boiler is to fit a thermal store (big hot water cylinder) between the boiler and the UFH, I have this arrangement and find it works very well. the boiler heats the water in the thermal store to 60C and the UFH is fed via thermostatic mixer valve, the boiler runs for one long blast to heat the thermal store and the UFH runs for several hours on the stored heat not calling on the boiler until the store has cooled down. The boiler is at it's most efficient when run this way.

Comic Book Guy

Thanks for the advice Dolan, will defo mention it to the plumber tommorrow and see what he thinks.