Cavity block for open fire?

cormie

Hi,
Getting the idea from my storage heater, which holds heat for the whole day in cavity block after being heated in the night, would the same work if you were to chuck a cavity block into an open fire? As it is now, once the fire is out, the heat quickly goes.

Any thoughts welcome

10-10-20

Yes, but it will look really ugly and will tend to topple out...
You can add a small firebrick to the back of the fire to do this. It also helps to prop the fire up somewhat.
The fire surround and rear plate will also do what you are thinking of. I don't really see a need for what you are thinking of.
Don't forget that ~70% of the heat in an open fire goes up the chimney...

JackieRyan

Hi
not quiet sure but if you put a cavity block in an open fire,won,t it explode if the fire gets really hot,

PeteHeat

Hi,

The standard cavity block will break up under the heat, if you are lucky and don't use a high density block it might not explode.

The firebrick will be safer of course it will reduce the size of your grate so less heat.

.

cormie

Thanks for the replies. What exactly is a fire brick and where would I find one? I'm not sure if there is any plate at the back of my fire, there's no heat at all after a while with the fire.

If 70% of the heat goes up the chimney, what would be the best way to block the chimney so I'd have 100% heat to the room when I have the fire on?*

Also, I heard that when you're not using the fire, it's good to blow up a balloon to block the chimney to stop the cold getting in and the heat out?

*joke

JackieRyan

If you like an open fire ,would you not consider a wood buring stove or a milti fuel burner more efficent in heating a room and less goes up the chimney and as there is a pan underneath the grate easier to clean out




cheers
jackie

PeteHeat

Hi cormie,

Sad to say 100% efficiency is not yet available, you can reverse the numbers using jackieryan's suggestion, a good stove will achieve 70% efficiency.

Careful using the balloon quite a few people got a shock when they forgot to remove it before lighting the fire !

However if you close off the air to the stove you can reduce the heat loss up the chimney by some 90%.

.

cormie

Thanks for the replies everyone.

It's just rented accommodation so I wont be investing in anything like a stove

Can anyone tell me what exactly a fire brick does and where I can get one please?

PeteHeat

Hi Cormie,

A fire brick also known as refractory brick is made from the same material as your fireback.

People used to put them around the sides and back of the grate to reduce the working size of the grate in an effort to save on coal.

I'm not sure it will actually help in a modern 16" fire grate, they are available from most fireplace manufacturers and some builders providers.

.

cormie

Thanks a lot, will have a look

lewis

Check to see if you fireback is cracked or broken, most firebacks life span can varie with use, if you have on big fires all the time the can crack very quickly, I would only use a fuel saver if you want to have smaller fires and move them closer to the grate or i would use them to pro-long my fireback.
But with a bit of common sense you can control the size of your fires with the amount of fuel you put in and where you place it and each time you go to top up your fire with fuel give it a good raking or shuffle to remove all the ash and be left with just the coals then top up your fire. you cant beat a real open fire, a whore to clean but the best heat

fmcc

Sorry lewis have to disagree about the best heat a stove is about 75% eff while an open fire 15-20% so you get 60% more heat from a stove vrs an open fire for the same amount of fuel. I know some people just love the open fire but their days are numbered imho.

lewis

What ever floats your boat, great heat from an open fire when your room is the standard size, stove then when she`s a big one, I guess im`not a fan of stoves, maybe I worked with them and fireplaces to long...

gsxr1

why bother putting anything in the fire. chimney Brest is built with solid blocks and doing the exact same already.

I put a stove in my fireplace. 10000% recommend them . I would never go open fire again.