Winter Sucks Money Up The Chimney

If, like me, you own a character home, it’ll have some unused and outdated features which need dragging into this century.

In this article, we’ll be looking at ways to deal with chimneys, because with the cost of energy these days, nobody needs a gaping hole in their house.

We’ve already detailed how to seal up windows and doors to keep your heat from escaping into the winter wilderness, but this time I’d like to focus on fireplaces.

There’s an architectural maxim that says happiness is directly proportional to ceiling height, and in the days before air conditioning, I know that held true. Keeping cool meant simply keeping the doors shut and letting heat rise, but keeping warm was easy, you just had to burn things in the fireplace.

These days we are aware that particulate pollution is a terrible problem for human health, and the cost of buying wood is substantial these days, with reverse cycle air cons much more cost-efficient at keeping homes warm, especially for people with rooftop solar.

From an energy perspective an open chimney is arguably worse than an open window because it’s a stack designed to suck hot air, quietly and efficiently, out of your house.

Really the only decent argument I’ve heard for an open fire is a romantic one, ie the sex is better.

Chimney Blockers Are A Good Start

Let’s face it, there may be a few times you really need the radiant warmth and atmosphere of an open fire. Humans have been watching “Bush TV” for millennia so rest assured, there are temporary solutions which fill this niche.

At my place energy auditors not only gave us a free shower head and some LED light globes, they supplied and fitted temporary chimney blockers to seal your fireplace whenever it isn’t in use. As a non-standard item for the REPS scheme where I live in SA, you must tell them on the phone you need these, or they’ll have to make a second appointment.

Made from felt, they simply jam inside the chimney, leaving a handle or two hanging down for you to grab. Much like a door snake, they’re not perfect but a massive improvement nonetheless.

The handle is a bit flimsy but we used this to plug up the chimney before the formboard, fan and light went in.

From Fireplace to Bookcase

If you are looking for a permanent solution, turn the fireplace into something new.

The top of your chimney will dictate whether you can put a terracotta plant pot, folded metal flashing or some other cover to stop the rain and wildlife coming in. Demolishing the chimney so it’s below roof level is also an option that’ll allow you to install more solar.

Inside there are a few options, but my solution is a simple box to form a bookcase with a salvaged drawer underneath.

Laying two extra pieces of formply on the top creates a solid shelf and covers the slightly arched opening.

Given a little more budget, I would probably install a floor console air conditioner which is designed to fit flush into existing fireplaces.

Not only do they pump heat out right at floor level, the filters are easily accessible for cleaning. Just be sure to keep little fingers and their toys out of the fragile louvres which direct airflow.

These units often replace an oil or gas fired unit with heating and cooling capacity. Image credit: My Efficient Electric Home

Repurpose Your Kitchen Chimney

With kitchens, there’s potential for an even better fix: induction stoves are fantastic to cook on, easy to clean and cleaner to use.

I struggle to get my head around just how fast you can turn an induction stove down when it’s boiling over, the control is brilliant. By inducing heat straight into an iron based pan, induction is faster and more efficient.

The realtor’s advert for my place featured a genuine wood-fired stove which sadly thankfully was too rusty to contemplate using. While I have seen fridges poked into fireplaces before, we decided to reclaim some bench space and reuse the chimney as a range hood.

Using a wet brick saw inside the house was going to be messy? Who knew?? At least we could fit a dishwasher when the existing oven came out of the cupboard.

This meant demolishing the brick surround from a couple different generations of stove and finding a horseshoe and a brass bevel gauge built into the hearth. Then I spent a couple of weekends fashioning some formply into a new custom cabinet and (re)routing some wiring for both the stove and oven, plus light and exhaust fan.

I’ve heard a horseshoe in the hearth may have mystic significance but I suspect someone just dropped their bevel gauge?

Cooking Without Gas

They’re available new, but I’m not lunatic enough to reinstall a wood stove. It would only be romantic until it caused a divorce.

In 2025 we can look back on the wood and coke-fired stoves my grandmothers both used as primitive. Yet in the mid-1950s, they would have found gas a great improvement; it is easier and cleaner than any solid fuel, so I want to underline a point here:

Gas is clean-ish compared to coal, but compared to induction, gas is filthy.

Even if it was cheaper (it isn’t) progress means we’re leaving the gas industry lies to last century.

In reality a gas stoves are known to fill your kitchen with NOx, Benzine and other carcinogens, but of course the gas industry doesn’t market what they’ve known since the 1970s.

And of course we shouldn’t discount the fact an induction stove won’t set fire to the house or kill you with a gas explosion.

If you cut your sheets just right, there’s plenty of structure and enough gaps for ventilation of the stove top up from the bottom and out through the side drawers.

The biggest worry about installing electric stoves is the question of how much power they need. While our 900mm unit is rated for 11kW at full steam, in reality you never have every burner running so it never needs 47amps at 230 volts.

Image credit ECA WA

Consult the good book and you can legally use a 32amp supply. In my case I used the original stove cable to supply the oven, and a new 6mm² cable to feed the stove top.

There’s a big hole full of fresh air in this house. Plus we now have wiring drilled through the chimney from inside the roof space to offer a plug base each for lights and fans.

ExtrAction Stations

Fitting a manufactured domestic range hood with fan, filter and light may be possible but I know from experience you can sometimes struggle for space inside the chimney.

Timber screwed inside the chimney takes wood screws (green arrows) to fix this board in place, as indicated by the red line. Note the flaps on the back of the fan to stop backdraft. On the right I’ve added a profile cut stip to fill the uneven gap, then struggled with upside down caulking.

My first attempt at a range hood used a piece of white melamine faced chipboard. Turns out that’s not stiff enough so replacing it with phenolic faced formply prevents sags.

The second try used the same cheap exhaust fan and a genuine Australian made DraftStoppa to prevent backflow. Due to a clash between these two, the fan mounting lugs would foul the fan blade when it wasn’t turned on, and this flaw was a most instructive feature.

When the wind howled outside, air pushed in through various gaps all over the house, which made the fan turn like a windmill, producing an audible clicking noise as our heated atmosphere disappeared up the chimney.

The gap on the left is too big for caulking. Rolling a LEGO tyre along the irregular surface gives you a line to cut to (in red). This cardboard template means you can profile cut a filler piece with a jigsaw, as seen above.

With gaps around the edge it’s remarkable how much air will still be pulled up the chimney without using the fan.

For round three I’ve bought a more powerful fan with integral shutters, and this time we’ll caulk the edges.

Atomic Coffee – so strong it shakes the building

Formply is super strong, comes in consistent sized sheets and is very easy to clean. Seriously, you can use it as a workshop bench and hit it with high aromatic brake solvent to wipe off motor oil, so I’ve rebuilt a whole kitchen with it.

My biggest tip for this arrangement is remember to clean the fan occasionally and if you really want a Rolls Royce job, get a commercial mushroom fan with a shutter, which doubles as a waterproof hood on the outside.

Insulation For Winter Will Also Help Through Summer

That’s a wrap for my series on DIY around the home to keep warm in winter: if you haven’t already take a look at my tips on insulation for windows, doors, and the rest of the house.

As winter withdraws it’s cold feet and we head into who knows what, I hope this series of posts has helped explain the importance of trapping the energy you can harvest from your roof for use after sundown.

These tips will more or less help through summer too, lets hope it’s not too brutal.