How To Keep A Poorly Insulated House Warm

Are you looking for ways to keep your poorly insulated home or room a little warmer throughout the year, especially in the colder winter months?

Here are a few fast inexpensive suggestions as well as some other longer-term and more permanent solutions you should maybe consider exploring in the future.

According to the experts’ heat is lost or gained mostly through the walls (35%) of your home, then through the windows, doors (25%) and roof (25%), and astonishingly enough through the floor (15%).

a woman sitting indoors snuggled to a blanket with a wool cap

Quick-fix options to consider

Firstly, let us explore the “quick-fix” options that can be done to make a difference in your home or rental.

You might think of this as something silly or something that could not possibly make a difference, but I can assure you that all of these small and insignificant changes do help.

They add up in the end, especially when combined (less is definitely not more in this case).

1. Sealing windows and doors properly

a hand demonstrating that a window is being shut by operating the windows handle

By installing door sweeps or seals on your doors you can completely eliminate those little bits of cold air entering and can make a massive difference, especially on a cold windy day.

There are many DIY options on the market that you can choose from that don’t require any special tools to install.

Just by installing something to seal off windows and doors properly, you are eliminating the pesky cold air from whisking through your living space cooling rooms as far as it travels.

2. Rearranging furniture

Together with stopping the little pesky breeze from entering, try and arrange your furniture in such a way to avoid having your seating in a draft.

3. Welcome the sunshine into your home

a home with lots of sunlight entering through the windows

The other little thing you could do while keeping your windows closed (of course) is to make sure you get the natural sunlight and heat flowing into your home or room through the windows.

So, make sure to keep those curtains open during a hot summer’s day and embrace the natural heat accumulating in the room.

Once the day is over and the natural warming rays of the sun have done the job of heating your room up, it is time to close those curtains to make sure you keep the generated heat inside.

The thicker your curtains, the better they will function as insulation. If you have blinds or shutters, make sure to close all of them to increase the barrier.

4. Put your ceiling fan on reverse spin

ceiling fan with an arrow pointing at the reverse switch

The other neat little trick I often make use of myself is the ceiling fan, I will explain.

Most ceiling fans have an “S” or “W” (summer and winter) switch, by flicking the switch over to winter the fan spins in reverse, circulating air in a suction motion over the ceilings and down the walls.

This works wonders to circulate the warmer air and eliminate the cold lingering air.

5. Put some rugs down

a rug laid down on a hard floor

Another quick-fix option is making use of a rug, especially in areas of the home that is not carpeted and have cold tiles or concrete as a floor covering.

Rugs, although decorative as well create that warm feeling under your feet and do assist in helping keep the warmer air in. A lovely fluffy blanket on the sofa couch (or close by) wouldn’t hurt either.

Tip: If you lay a rug down on a hard floor, put some shelf matting under it first to avoid the rug from slipping around.

6. Maybe considering a gas or electrical heater?

heaters place next to each other

I also just want to mention to those of you considering a heater, make sure when you are using a heater that the flow of hot air is not restricted.

To give you an example of restricting the hot air would be to place your heater right in front of your lounger chair.

Yes, you will be lovely and toasty but the rest of the room will take longer to increase its temperature due to the flow (or the lack of it).

Also make sure to close off rooms you do not need to include, like your empty spare room for example.

So be mindful of where you want the heat and where to place your heater.

Oil heaters are quite efficient for longer use periods and are more specific to heating an entire room, instead of one immediate area.

Gas heaters are extremely effective but generate a lot of moisture. So just be mindful when using this type of heating.

The longer-term and costlier solutions to consider

Now, move on to the more long-term or permanent options that are available to you.

These options unfortunately do not fall under the “do it yourself” category so take time and do your research to make sure you have the right professionals, using the right materials for your home insulation.

Maybe some you can attempt as a DIY project, just make sure to get all the right information about the products and the application (especially the application process).

You can always speak to a supplier for advice, for example going to your local building or hardware store that stocks the products and explaining to them what you currently have and what you would like to do.

They will without hesitation assist you with advice and tips.

I always suggest speaking to two or more different sales representatives, sometimes you get someone that has a completely different approach that could even be a better solution for you and your unique situation.

There is also soo many different informative videos and instructions online that can be studied to assist you.

1. Get the right insulation for your home and climate

insulation material place on a plan for a house

In South Africa we have different climates in each region, meaning your insulation has to be tailored to where you live. The colder areas such as Johannesburg (eGoli) or Pretoria (Tshwane) will require thicker ceiling insulation than the warmer humid subtropical climate in Durban (KZN) would require.

The most commonly used insulation for residential properties is fiberglass (Aerolite), polyester (Romatherm and Fabufill), recycled PET bottles (Isotherm) as well as certain mixes such as Earthwool with ECOSE technology (Knauf) and fiberglass with Flexiwool (Granric).

I also just want to give you more background and current pricing on a few of the more popular choices.

Aerolite insulation

Aerolite or “think pink insulation” is very common all across SA due to the fact that it works well, is very cost-effective, and can easily be cut for installation, which means your professional installer will be in and out.

A roll of your thicker 135mm (6 m² coverage from a roll) will cost about R600.00. The thinner 100mm option (7.2 m² coverage from a roll) will cost you about R500.00 per roll.

Isotherm insulation

Isotherm (green in colour but also eco-friendly) is the new kid on the block and unfortunately, because of it being so new SABS hasn’t given it the stamp of approval as yet.

This product works wonders, especially for households who suffer from allergies.

This would also be your go-to product, should you wish to make insulating your property a “do it yourself-er”, many consumers cover their geysers and hot water pipes with it to save on their bills.

Easy to cut and install (even has rolls that come pre-cut in two different sizes). Per roll is a bit more expensive than its pinker cousin.

The thinner 100mm option (7.2 m² coverage from a roll) will cost you about R600.00 per roll while the thicker 135mm (6 m² coverage from a roll) will be R700.00 each.

Fabufill insulation

Fabufill is a popular polyester product to choose from. This product is SABS approved and can certainly be described as quality, also an added bonus is that it is made from 80% recycled material making this product one of the greenest insulations in SA.

Prices on the thicker 135mm can range, but you can work on about R530.00 per roll. The thinner 100mm option ranges from R410.00 to about R490.00 per roll (same coverage as previous products mentioned).

2. Moving onto ceiling insulation

A great product we have in SA is called Isoboard which can be used for everything from the floor, walls, and all the way up to the roof.

It assists with the regulating of heat and cold as any other insulation would do, replacing your old ceiling boards with Isoboard is a great way of regulating the temperature in your home.

This product even comes as an IsoPine option that has some beautiful grooved and beveled finishes to create an entirely new look to a room.

3. Wall insulation

As mentioned previously, Isoboard is an outstanding option, for new builds as the boards are built into the cavities of double walls (external and supporting walls) during the building process.

Isoboard works fantastically for wall insulation, especially when combined with the Isoboard floor and ceiling insulation.

Another way to insulate walls of existing properties, should you wish to try it as a DIY project is to prepare walls of certain areas that are especially colder or warmer than other areas’ walls and add a layer of polystyrene.

You can then decide on maybe doing a fun new wallpaper or cladding to create a new feature or rock wall, the possibilities are endless.

4. Floor insulation

Isoboard is an excellent option to consider when building your new home as it is cast into the floor slab.

The other option is underfloor heating which might not be the most economical option as all floor coverings such as tiles and carpets first have to be removed and only then can underfloor heating be installed and another floor covering of choice will have to be calculated into the cost.

This could be something to consider when already wanting to replace current flooring to update the look and feel of the property.

The electrical bill is still something that will have to be taken into consideration when calculating the cost and the maintenance of underfloor heating.

You can also look at carpeting rooms, removing tiles, insulating underfelt, and doing some vinyl or laminated flooring.


As you can see from the various options (lower cost and higher cost), there are quite a few things that can be done or planned to help better regulate your home’s temperature.

Most of the lower-cost items can be done in rentals too (as long as the owner or rental agent is aware of the issue and plans).

You can always speak to the rental agent or owner about the insulation issues, in some cases, they might even offer to accommodate you with an upgrade or two.

I know in the past we also offered to do the work or pay for it (by a reputable or registered installer) and we received a small reduction of rent for a few months to compensate for the fact of upgrading the owners’ home for them.

It becomes a win-win situation as both parties are happy at the end of the day.

The best option is still planning properly and having all the insulation built into your home from the beginning but like all of us know, building material and their cost just seem to multiply, especially when wanting to do things properly.

Well, I hope some or all of these pointers help you decide what you will be doing to improve your home or rental temperature.

I am sure there will be quite a few DIY projects on your to-do list after reading this – as long as you have fun improving your living space (and it works or looks better than it did before, of course!)