Keeping heat inside a shed is essential for use during the colder months of the year. Methods such as insulation and electric heating systems are a great way to maintain warmth inside.
Converting a shed for use as more than just a storage space is becoming increasingly popular. Garden buildings are ideal for use as a small workshop, garden office or even a place to relax and unwind. One of the biggest considerations is how we can maintain a comfortable temperature inside the garden building throughout the year and not just in the summer.
The challenge with a garden shed is that they are typically constructed using 12mm tongue and groove cladding on the walls. This does little to prevent heat loss, resulting in the temperature inside often being the same as outdoors during the colder months. If there is not an additional heat source inside of the shed, there will also not be any way to get warmth inside in the first place.
For use as an additional room, we need to make some conversions to the shed to get better control over the temperature. First, we need to make sure the building is capable of holding warmth inside and preventing heat loss by using insulation. Once completed, we can add a heat source to increase the temperature inside.
Both of these steps can require quite a big upgrade to the shed. In some cases, a new garden building such as a log cabin may provide the best solution as the structure can be designed for keeping warm.
The most effective of keeping warmth inside a shed is to install insulation. The cladding on most sheds is not thick enough to keep heat inside during the colder months of the year. Without insulation, heat is quickly lost, leading to high costs to try and maintain a consistent temperature inside.
Inside a residential property, the room temperature is around 20 degrees. If we want to create a comfortable atmosphere inside the shed, we should aim to get as close to that as possible. If we are storing electrical items inside, a poorly regulated temperature and exposure to freezing conditions could lead to components becoming damaged.
Attempting to heat a shed without insulation is also extremely expensive. If the shed is losing heat as fast as it is being produced, a heater is required constantly. A good electric heater has a power output of 2kW. Running this for just 10 hours per week could add around £200 to the average electricity bill.
Plenty of choices are available when it comes to insulating shed walls depending on the budget available and the performance required. PIR rigid foam insulation boards provide the best performance but can be the most expensive.
The insulation boards contain rigid foam and an aluminium foil exterior to reflect heat. This type of insulation board also has a good fire safety rating which is important in a garden building. One of the benefits of insulation boards is they can provide high insulating values, even at low thickness.
For installation, the insulation boards are cut to fit tightly in-between the internal wooden framing of the shed. This works great on shed walls and the lightweight insulation boards are easily fixed into position.
A lower-cost option for shed insulation is a foil-backed bubble wrap product. These contain air bubbles inside that slow down the rate at which heat passes through. The foil on the outside also works to reflect heat.
Once the insulation has been installed, the shed walls can be boarded over to create interior walls that hide the insulation. OSB or plywood make a good choice for the interior walls of a shed.
Insulating roof & floor
Insulating the shed roof and floor follows a very similar process to the walls. Insulating the roof is essential as a large amount of heat will be lost through the roof as the heat rises throughout the day. As insulation works both ways, it can also stop heat from direct sunlight from getting in during a hot summer’s day.
Rigid foam insulation boards are the best option for a shed roof. As they are lightweight, they can fit between the interior rafters without putting extra stress on the timber. The trick is cutting the insulation tight so that it slots in place without the need for additional support.
Insulating a shed floor is more difficult and not always worth it. The best time to insulate the floor is during construction. Insulation boards can be fitted between the wooden framing in the foundations and the floor installed on top. If the shed has already been installed, it can be best to use a dense flooring product that will reduce heat loss from below.
Use an electric heater
Once the shed is insulated to reduce heat loss, we can decide how to get heat into the shed when the weather outside is cold. As heaters require a lot of power, the best method is an electrical heater. Solar products do not produce enough power to consistently run a heater.
This is going to require electricity installed into the shed, so the building needs to be completely watertight. Any electrical work should always be carried out by a quality electrician and needs to meet part P of the building regulations. An armoured cable is usually buried underground between the house and garden building to supply electricity.
Electric heaters come in a variety of power ratings starting from 0.5kW and going up to 2.5kW and above. For a small and well-insulated shed, a 1kW heater should provide enough output to keep the interior warm. Larger garden buildings are better suited to a higher performance heater such as a 2kW model.
Types of electric heater
Lots of choices are available when it comes to selecting an electric heater and most are very affordable to purchase. Electric heaters are near 100 percent efficient and if you purchase a 1kW heater, it will use 1kW of power regardless of the type. There is often no efficiency saving when choosing between different types of an electric heater.
Fan heaters are very popular for heating cold spaces such as garden buildings. A benefit of fan heaters is the near-instant heat, with little to no warm-up time. This is great for using a shed during the colder months as the interior can quickly be brought up to temperature without planning in advance. A fan heater works by passing air over a metal element which is heated, resulting in the warm air circulating around the room.
Fan heaters are often the lowest cost electrical heater to purchase and can start from as low as £15. A downside is that they are designed for running in small bursts rather than continuously. The heater can be noisy which can be distracting if the shed is in use while the heater is running.
A convector heater provides lots of flexibility, as well as good value for heating a garden building. Convector heaters work by heating the air, which rises and moves around the room. Unlike fan heaters, they do this quietly, meaning they can go unnoticed when in use. Most models are freestanding, allowing the heater to be repositioned and moved around inside of the shed.
The design of most convector heaters is very similar, featuring a large white panel. A drawback is that the air can sometimes feel dry when heated using convection. As the air is heated, we also want to ensure there are no drafts in the shed to avoid losing heat.
For sheds that you plan to spend a significant amount of time inside, such as a garden bar or office, oil-filled radiators are usually the best solution. Oil inside of the radiator is heated up and then retains its temperature. While oil-filled radiators have a longer warm-up time, they also take longer to cool down. The radiator carries on producing heat for a long time once it has been turned off.
With no mechanical parts, oil-filled radiators are quiet to run without causing distractions. They can be larger than other electric heaters due to the thins needed to distribute heat. Many options include wheels to be easily moved around the room.
Guide: Best heaters for a shed
Position the shed facing the sun
Where a shed is positioned can make a big difference to the feeling of warmth inside. The sun is a natural heat source all year round and we can position a shed to take full advantage. Positioning the shed in direct sunlight and not being blocked by any trees will let as much sunlight get to the building as possible.
The side of the shed with the most windows should be facing the sun to let plenty of warmth into the interior. The windows will often intensify the feeling of warmth coming from sunlight.
Painting the shed in dark colours will also allow maximum warmth from the sunlight. Dark colours, such as a black roof, are better at absorbing heat from sunlight. Consider painting the shed in a dark brown colour that still looks good and absorbs heat from sunlight.
Best way to heat a shed
Overall, the best way to heat a shed is through a combination of insulation and an electric heater. Insulation is essential to keep a shed warm, otherwise, heat is quickly lost through the walls and roof. Without insulation, it will be difficult to have much effect on the interior temperature, without running a heater constantly.
With insulation installed, we can use an electric heater to produce warmth inside the shed. As electric heaters can be expensive to run, they are designed to be used in small bursts. Fan heaters are great for quickly warming a cold space and provide good value for money.