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How a Cob House Will Save You Money On Your Fuel Bill

Updated: Jul 13, 2023

cob house with sunlight
Cob house cheap energy bills

In these days of high energy bills (and high everything bills) and for the sake of the environment, we need to look at ways to light and heat our homes sustainably and cheaply. We need to find a long term solution that will be kind to the planet and to our wallets.

Cob is the ideal solution. Because it contains a high proportion of sand and gravel, it has a high thermal mass. This means that it holds the heat like a storage heater.

It absorbs the sun's energy throughout the day and then sloooowwwwllly releases it at night. Easy, right? Nature's heating without having to dig and release harmful greenhouse gases.

When I design a cob building (and teach you to build on our 4 day Complete Cob Building Course) we use a highly insulative material, like straw bale which stops the precious heat escaping.

But the insulating properties of straw bale is not the only way to generate heat and light. Design and location are essential ingredients too.

Cob house energy efficient sun-light
Beautiful sun-light in roof

Let me invite you to dream. On waking up in your cosy bedroom, you go to the kitchen which, because it's facing east, is filled with beautiful, bright sunlight. You sit at the kitchen table with a cup of tea and break your fast bathed in early morning sun.

The triangular roof-light acts like a sundial letting in rays throughout the day onto the beautiful cob floor which is finished with linseed oil and bees wax for their waterproofing properties.

Sunlight pouring onto floor
Sunlight in cob house

In the evening at the golden hour, after a long day at work, you relax and read a book in your sitting room, which faces west, and catches the last beautiful rays of the sun.

At night, when the temperature drops and the heat from the day starts to radiate out of the walls, the insulating straw bales stop that heat escaping and keep the precious cost-free energy in the house.

The combination of location, orientation, cob materials and use of windows and doors is key to making your home as energy efficient as it gets.

Energy efficiency does not have to be complicated or expensive. If you find yourself spending too much money it's probably wrong or unnecessary.

Straw bales cost just a few pounds per bale, and are three times more effective at holding heat in than building regulations state they should be. I generally find all the materials I need to build the walls on the land where I'm building; there is almost always enough clay sand and gravel just sitting under the ground for free.

Looking to save money on your energy bills and build an energy efficient cob house? Then book on a cob building course. To find out more check out our Complete Cob Building Course Page or email me (Kate) directly at

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