Any idea of gas used by boiler vs gas fire?

pinkteapot

We have a 4-bed house. I am home alone two days a week. It seems really wasteful to have the central heating on (and our radiator valves are old and fiddly so I can't be bothered adjusting the radiators in the rooms I'm not in as I'd have to adjust them back before the evening).

Usually I close the doors to the lounge and dining room (separate rooms but off one another) and put the gas fire in the lounge on. This heats both rooms, which are the ones I primarily use.

My assumption is that the fire uses considerably less gas than the boiler. Looks like it has more flames but they only burn orange rather than bright blue.

Is that a fair assumption?

SailorSam

If the flames are burning orange the fire probably needs a service, or at the very least a good clean it's probably sooty.

jimbo_the_jetset

So many factors to take in for that calculation, boilers/fire age, efficiency, room/house size, insulation, weather.

I have always thought that a fair chunk of heat from a fire goes up the chimney, i.e. is wasted, and prefer our new(ish) boiler.

Only way to know for your situation is to do a test for a week or two using each method taking readings from the meter.

p.s. it may be moneysaving to renew your radiator TRV's if they are not working. Shouldn't cost much or can be done DIY.

macman

Your assumption is probably correct, but since both devices are fitted with rating plates giving the output, you can check this easily.
The boiler will cost more to run, but is producing more heat. more efficiently. You are not comparing like with like.
The flames should not be orange/yellow, this indicates incomplete combustion. When was it last serviced?

rustyboy21

It's what works for you, at the end of the day. Your fire is only heating 2 rooms, whereas you CH is heating the whole house.

It also depends on what type of fire you have. Do you know the make/model of fire you have?

I sell fires for a living, but my fire hasn't been on for over 12 months, as I like the whole house warm, instead of a couple of rooms and you going from cold to warm, when you want to make a cuppa or go the loo. A boiler will use more gas, but will heat the house, a fire will use less gas, but only heat a room or two. The boiler will use the gas used more efficiently, normally

WestonDave

To be fair a fire with coals etc in will often create red/orange flames via the coals, but if it hasn't been serviced in the last 12 months its worth getting it checked.

It also depends on the type of fire - open pretty fires are apparently fairly inefficient - they are there for show rather than efficient heating (as stated by the fire shop when we were looking at nice arty open basket type fires!) whereas the closed in stove ones are often more efficient as they heat up the "box" which transmits the heat to the room rather than just straight up the chimney.

The other thing to possibly explore is whether you can fit a programmable thermostat onto the system - from around £70 plus fitting these would enable you to programme the system in advance to keep the house warmer on the days you are home and not on the days you are out.

ic

Gas fires have varying efficiency ratings - I know mine is 6kW, but 3kW of the heat generated goes up the chimney in the exhaust gases. My boiler is 24kW and less than 2kW goes out the flue as lost heat. Also the boiler is self modulating and thermostatically controlled - i.e. it turns off and on automatically as the temperature is reached, and even when it is on it probably isn't running at full capacity as the rooms are close to temperature anyway.

I recently fitted automatic TRVs to a few of the radiators, which effectively zone the house. My living room is no longer heated on work day mornings to full temp, whilst the bathroom is not heated to full temp in the evenings.

Jaynne

It doesn't matter how efficient your boiler is, unless it is tiny, it will still draw its full power most of the time. A 15kW boiler draws 15kW of power - though it won't be constant as the thermostat turns it off. It might be 90% efficient and therefore giving you 13.5kW of heating but you will still need that full power to heat your house.

A gas fire will probably draw 6kW constantly and even though a decorative one might be 30% efficient and so giving you 1.8kW of heat it is still drawing less than half the gas of your boiler.

Of course your boiler is heating your whole house but if you're only in one room that probably doesn't matter to you.

ed110220

SailorSam wrote: »

If the flames are burning orange the fire probably needs a service, or at the very least a good clean it's probably sooty.

Is it actually the flames that are orange? If it's working normally, the flames will be blue/colourless and may be difficult to see, but they'll heat up some fake coals or something like that, which will glow orange.

If the flames really are orange, that indicates incomplete combustion which is inefficient and can produce carbon monoxide.

ormus

only the latest gas fires are as efficient as modern boilers. in % terms.
and half of that heat goes straight up the chimney.

pinkteapot

Thanks for all the thoughts.

I don't know anything about the rating of the fire. It has one ignition/control dial and it's a "Fireflame Gold Deluxe by Main". No other labels or anything with information.

It was serviced just over a year ago - the guy who came round laughed at how retro it is. Think it was put in when the house was built in 1990 and this is the only pic of it I can find online:



It's not just for effect - if you close the lounge doors so you're only heating the one room, it HEATS it.

TRVs - I wish. Heating system also dates from 1990 and we don't have TRVs. We have a standard double pipe system with the radiators having one 'fixed' valve (the one you only adjust to balance the system) and one 'temperature' valve which is just marked with a +/-. Most of the valve caps for these are knackered inside though, so to adjust the valves you have to take the cap off and use pliers/spanner.

Servicing both the fire and the boiler is on my list of February jobs so it'll get checked out again soon. The flames are blue when you first put the fire on and turn orange after a few minutes. You've got me worried, but it was the same before and then after the last service. Hmmmmm.

Fire gets used a lot in the depths of winter as the lounge radiators just don't heat the room. It's a 4m x 5m room. One radiator is behind the sofa and one is in a large bay window - helpful positioning.