
As you plan your beautiful new sunroom addition, intended as an extended living space, you may be asking yourself, "How will we keep this room comfortable throughout the year?" To help you design the ideal space, here are some heating and cooling methods to avoid – and the ones you should consider – when building your dream sunroom in London, Ontario.
Extending Ductwork from Your Home to the Sunroom
At first, it may seem like a great idea to have your house’s thermostat control the temperature in your sunroom as well. However, there are a few issues with this approach.
For example, a room made mostly of glass will have a different temperature from the rest of your house, so simply extending ductwork won’t be enough to bring the sunroom to a comfortable temperature. Even if you set the thermostat to 72 degrees, the sunroom may not reach the same temperature as the rest of the house. To get the sunroom more comfortable, you’d need to adjust the temperature of the entire house, which will lead to higher energy costs. Additionally, when the sunroom is not in use, the rest of your house may no longer be at a comfortable temperature, forcing you to constantly adjust the thermostat to stay comfortable in both your home and the sunroom.
- Temperature Differences: A room made mostly of glass will have a different temperature than the rest of your house, so extending ductwork alone won’t be enough to regulate it.
- Increased Energy Costs:To make the sunroom comfortable, you'll need to adjust the temperature of the entire house, leading to higher energy costs.
- Inconvenience:When the sunroom isn't in use, the rest of the house may become uncomfortable, requiring constant thermostat adjustments to maintain a desirable temperature.
Instead, we always recommend having an independent source of heating and cooling in your sunroom in London, Ontario. This allows you to monitor the temperature of your sunroom by itself, separate from the house. Some examples of independent heat sources include:
- PTAC Electric Heating & Cooling Unit A separate unit with its own thermostat built into the wall of your sunroom, providing year-round comfort with independent control.
- Ductless Mini Split An indoor unit mounted on the wall, connected to an outdoor unit, offering independent temperature control for the sunroom with both heating and cooling options.
- Gas Fireplace: A supplemental heat source to boost temperature in your London, Ontario, sunroom, adding cozy ambiance. It can also serve as a primary heat source, in which case a separate A/C-only ductless mini split is recommended.
The Drawbacks of Using Low-End Space Heaters
While using a space heater may seem like a cost-saving option in the short term, it won’t be beneficial in the long run. In southwestern Ontario, where winter temperatures can drop to -20°C, space heaters typically don't produce enough BTUs (British Thermal Units) to adequately heat your sunroom. Additionally, they can cause condensation issues, as sunrooms tend to have higher humidity levels due to their exposure to outdoor elements and plants. This can lead to mold or mildew growth over time. Some space heaters, particularly unvented gas models, may emit pollutants like carbon monoxide or lower oxygen levels, while electric heaters can dry out the air, causing discomfort. Furthermore, space heaters are meant for short-term or occasional use, and relying on one as a primary heat source can wear it out more quickly, shortening its lifespan.
- Space heaters can cause condensation in sunrooms, leading to mold or mildew growth due to higher humidity levels from outdoor elements and plants.
- Unvented gas heaters can emit pollutants like carbon monoxide or lower oxygen levels; electric heaters can dry out the air, causing discomfort.
- Space heaters are meant for short-term use; relying on them long-term can strain the unit, shortening its lifespan.
Why Your new Sunroom Needs a Heat Source
If you’re planning to use your sunroom in London, Ontario, year-round, choosing not to install a heat source in your sunroom would make it unusable during the winter months, limiting its comfort to just a few months a year. This can also lead to furniture damage, as extreme cold and fluctuating temperatures can harm items, especially wood or fabrics sensitive to temperature changes. Without a heat source, you'll miss out on enjoying the unique atmosphere of your sunroom in colder months, such as reading by natural light, watching snowfall, or having a peaceful retreat. Ultimately, not adding a heat source to your four-season sunroom is a missed opportunity and a waste of investment, much like buying a boat without an engine!
- Furniture Damage: Extreme cold and fluctuating temperatures can damage furniture, especially wood or fabric-sensitive items.
- Missed Opportunities: Without a heat source, you miss out on enjoying the sunroom during colder months, like reading by natural light, watching snowfall, or having a peaceful retreat.
- Unappreciated Investment: Failing to add a heat source to your four-season sunroom is like investing in a boat without an engine—you're not getting the full benefit.
Trust the Experts: The Do’s and Dont's
A properly heated and cooled sunroom is key to making it a comfortable, year-round space. Let’s quickly recap the “Do's” and “Don'ts” for heating and cooling your sunroom!
- Don’t: Extend ductwork from your home to your sunroom.
- Do: Use an independent heating and cooling system, such as a PTAC unit, ductless mini-split, or a gas fireplace, to maintain a comfortable temperature in your sunroom without impacting the rest of your home.
- Don’t: Rely on low budget space heaters.
- Do: Invest in a more efficient and long-term heating solution to ensure consistent comfort in your London, Ontario, sunroom year-round.
- Don’t: Skip a heat source altogether.
- Do: Install a reliable heating solution to ensure your sunroom remains comfortable in every season.
Peace of Mind with Proper Heating & Cooling
Ensuring that your sunroom remains comfortable year-round requires thoughtful planning and careful consideration when selecting the right heating and cooling system. As we discussed in this article, extending ductwork from your main home or relying on low-end space heaters may seem like convenient solutions, but they come with significant drawbacks—from inefficiency to potential safety concerns.
Instead, we recommend investing in an efficient system such as a PTAC unit or ductless mini-split. These solutions offer independent control over your sunroom’s temperature, allowing for year-round comfort without affecting the rest of your home. Moreover, these systems help prevent unnecessary energy consumption and rising costs.
With the right system in place, your sunroom can become a beautiful and functional extension of your home, providing comfort, style, and enjoyment no matter the season!

Written by: Caleb Teichroeb, Sunroom Design Consultant
Four Seasons Sunrooms & Additions - London, Kitchener/Waterloo
Keeping your sunroom comfortable year round: Here’s what you need to know!
Avoid common heating and cooling mistakes in your sunroom. Learn why duct extensions, space heaters, and no heat sources can lead to discomfort and high costs.
Tags: guide, heating and cooling, home addition, home renovation, sunroom
Category: Maintenance, Sunrooms




