(Updated 2023)
Choosing the right heater can keep your garden building warm and toasty at any time of the year. With so many to choose from, it’s important to find a heater that warms up fast and provides a powerful heat output.
One of the many benefits of a garden building is the ability to use it throughout the year and at any time of the day. Despite the name, a summerhouse is not just for the warmer months and with adequate insulation can be used all the way through autumn and winter. We use our summerhouse as a garden office and with the help of an electric heater, a comfortable ambient temperature is maintained in all seasons.
Of course, having an electric supply installed is essential if you plan on heating your garden room. For most installations, the cabling is installed underground and runs directly from the fuse box inside your home. Heaters can consume a lot of electricity and soon increase your bills with daily use. The power output is measured in Kilowatts (kW) and a higher output provides more heat but also increases running costs. The average UK electricity cost is 16.3p/kWh and running a 1kW heater for an hour each day will add nearly £60 to the average electricity bill.
Electrical heaters produce either convected or radiant heat, which can affect the feeling of warmth and how heat is distributed around the room. Convected heat works well for larger environments. The air is heated and rises to circulate around the room, heating up the air temperature inside your garden building. Radiant heaters (such as halogen) work by radiating heat in the direction they are facing and heat objects instead of the air. Radiant heaters are better for drafty buildings where warm air can escape easily.
5 Best Heaters
This site is reader funded. We may earn a small commission if you buy through our links.
With so many choices available, it can be difficult to decide on the best heater for your summerhouse or log cabin. Let’s take a look at our top 5 recommendations.
ProBreeze Mini Ceramic Fan Heater

A portable solution featuring quick warm-up
Sometimes, a small heater that does its job well is all that is required. This mini fan heater from ProBreeze is a great compact option to provide instant heat. Despite its size, it packs a 2kW heat output which is plenty to make a noticeable difference inside a log cabin or summerhouse. Two heat settings are available including a low power (1.2kW) mode to reduce running costs when only a low output is needed. The inbuilt thermostat also allows for improved efficiency to avoid heating up the room more than required. If portability is important, this heater can easily be moved around, including to be placed on a table.
For us, this heater makes a great choice for a garden gym. The instant heat-up is ideal for switching on just before a workout to take the chill off on cold days. The clever safety features include anti-tip protection which switches the heater off to avoid an unsafe situation.
Delonghi TRRS 0920

Well-built & long-lasting warmth
When it comes to home appliances, Delonghi has a reputation for well built and good value products. The TRRS0920 oil-filled radiator provides long-lasting warmth for even large garden buildings thanks to its unique thermal design. Once oil-filled radiators are turned off, they hold their heat for a while, providing background heat and avoiding feeling chilly as soon as the heater is turned off. The design features adjustable knobs which make temperature adjustment easy and give maximum control over temperature and power settings.
For those who appreciate a simple set-up, this heater is ready to use without any assembly required. The design allows for simple movement thanks to in-built wheels. This makes it great for use in a garden office, as the heater can be brought closer to your workstation. The heat output provided is up to 2kW which is plenty for heating up a room even on the coldest days. The anti-frost feature provides an added benefit to keep any electrical equipment from getting damaged during the winter nights.
Pro-Breeze Ceramic Fan Heater

A great combination of features and performance
This high-powered fan heater from Pro-Breeze is easy to recommend as a go-to heater when using a garden office during the winter. The unit provides instant heat within seconds once turned on and quickly warms a medium-sized summerhouse. Severn operating modes are available including a high setting with a maximum output of 2kW. The eco feature rotates between the high and low heat setting to maintain a comfortable room temperature and reduce energy consumption.
The clever design features an 80-degree oscillation to move heat around the room with minimal effort. Using a slight tilt, heat is distributed faster to reduce run time. A remote control is included to operate the heater without having to get up to turn it off once the room is warm enough. The top of the unit features a clear design that indicates the current setting and whether the heater is plugged in. The only downside is that it’s not possible to use this heater with smart plugs as it requires a button press to turn on once connected to electricity. Overall, the unit is versatile and provides great heat output.
Dimplex 402BT Bluetooth Convector Heater

High output with smart functionality
The Dimplex brand is part of one of the worlds largest heating businesses and produces a huge range of heating systems. This clever convection heater features smart technology paired with powerful performance. The contemporary & clean design looks great in even the most modern garden room without looking out of place. The side features an LCD display and a selection of buttons for adjusting the heating. Setting the temperature is easy thanks to the up and down arrows and the inbuilt thermostat allows for maximum efficiency and automatic running.
Being a convection heater, this model runs near silent and you often won’t notice it working away in the background. Each side features integrated grab handles to allow the heater to be moved around the room when needed. Unfortunately, the design does not feature wheels but instead uses free-standing feet. Where this heater stands out is the inbuilt Bluetooth functionality which allows for the heater to be controlled from a mobile phone. The Dimplex Remo app features various controls including manual temperature adjustment and the ability to set up to four auto timer modes each day. The only downside is that smartphone Bluetooth is unlikely to reach the heater inside your garden room unless it is very close to your house. But the functionality is still great for when you are inside the room and using the heater.
Dimplex Oil-free Electric Radiator

Easy to use and high efficiency
The Dimplex brand has so many options available, they feature twice in our recommend heaters. This compact heater features an oil-free design which is compact and takes up minimal space inside a garden room. The white and grey design blends easily into the background and is small enough to leave tucked in a corner of the room. The controls are easy to use and make a good choice for those who do not want to mess around with thermostats or smart controls.
onboard wheels allow for this heater to be easily moved around to suit your needs. The oil-free design aims to provide energy savings vs traditional oil-filled radiators, whilst still providing a powerful heat output. Several models are available including 1.5kW and 2kW models.
Top tips for keeping your garden building warm
As we have discussed, a huge selection of heaters is available to keep your garden building warm. Choosing the right heater can be complex and there are many factors to take into consideration including the type of heat produced and how efficient your building is.
Make sure your building can hold onto the heat
Heating a summerhouse with no insulation is going to be fighting a losing battle on cold days. As fast as the heater is producing heat, it will be escaping through the walls, roof and floor. Most summerhouse walls are 12mm in thickness. While this is okay for cool summer evenings, it is going to have little impact in the autumn and winter. The result will be a heater running constantly and high running costs if your building is being used most days e.g. as a garden office.
If you plan on heating a summerhouse, we recommend installing insulation before. While this may seem like a big job, it can easily be completed over a weekend. Insulation boards are placed in between the framing on the interior walls. The insulation is then boarded over with a material such as plywood; resulting in thick walls that reduce heat loss and create a warm and comfortable atmosphere. Running costs will be reduced as once the room is up to temperature, the heater can be turned down or even to reduce electricity use.
Log cabins naturally come with thicker walls when compared to summerhouses. Most are available with 28mm or 44mm log thickness and some can even go up to 70mm. We find 28mm wall thickness is okay for use in spring, summer and autumn, but throughout winter is going to struggle to maintain enough heat for regular use. A 44mm log cabin is ideal for use in any month of the year. The thick logs work great to lock in heat and provide a comfortable atmosphere. Insulating the roof is recommended in a log cabin as the standard roof will not be the same thickness and a good proportion of rising heat will be lost.
Pick the best type of heater for you
How you are going to be using your summerhouse or log cabin is an important consideration when deciding which type of heater to purchase. Fan heaters provide heat instantly, which makes them ideal for heating up rooms fast. However, once the heat is turned off, the room quickly begins to feel cold again. Fan heaters can also be noisy when in use, which makes them unsuitable for running continuously. To take the edge off a chilly evening in a garden bar or gym, they make a good choice.
Convection heaters are commonly used inside garden buildings thanks to their flexibility and minimal warm-up time. The heater can be placed anywhere in the room and as the air is heated, it circulates around, providing a consistent temperature throughout. Convector heaters are also good value and one of the lowest cost heaters to purchase. A downside is that they are best suited to well insulated and sealed environments, where the warm air is not going to escape.
Electric oil-filled radiators are our recommended choice for heating a summerhouse or log cabin. While they take a while to heat up initially, they also take a long time to cool down, providing background heat after they have been turned off. In operation, they are near-silent which makes them great for leaving on whilst inside the room. Many feature wheels which allow for them to easily move around the room to be placed near you.
Guide: Heating a garden room
Take advantage of smart technology
Most of us have at least one piece of smart tech in our homes now, and it’s easy to extend to your summerhouse or log cabin. Some heaters are available in smart versions which allow them to connect to Wi-Fi and be turned on remotely, ideal for pre-heating your building before entering in the winter. Others will feature Bluetooth and can be controlled via a smartphone application.
There is not a huge choice of smart heaters available currently, but any heater has the potential to be smart. Taking advantage of smart plugs can allow you to turn on the plug and in turn the heater remotely. We use these to turn on our heater during the colder months.
Summary
Overall, a huge choice of the best electric heaters is available for warming a summerhouse or log cabin. Our favourite models include the Dimplex smart Bluetooth heater and the Pro-breeze ceramic fan heater. Before using a heater, it’s important to ensure your garden building is insulated. Insulation works to hold the warmth and create a room that is efficient and quick to heat.
During the last winter, we used a ceramic fan heater which provided a great boost of instant heat on the coldest of mornings. Our experience was very good and the remote control proved to be convenient to turn the heater off once the room had reached an adequate temperature. For most of the year, an oil-filled radiator provides great background heat for our garden office.

Maximum comfort is achieved through a mix of convection and radiant heat, which is given out from an oil-filled radiator. We recommend a 2kW model heater as a good balance between output and running costs. Anything less may struggle to heat up your garden room sufficiently over the colder months.
I heat my summerhouse with wet radiators, I have a underground insulated flexible pipe with 22 mm return & flow pipes. It is connected to my house main gas heating &works as another room.
It is much cheaper to run than electric heaters which I tried previously the normal radiators heat the summerhouse much quicker & the heat is retained a lot longer.
I have 45 mm walls & insulated the floor & roof with 50 mm celotex also fitted upvc doors & window with double glazing.
Well worth the effort as I use it as a cinema room every night all year round
This is what I’m thinking of doing Stuart,
How much lagging/insulation did you fix around the flow and return pipes? And what distance was it from your house to the summerhouse?