How to Make Your Granny Flat More Energy-Efficient

Granny flats are becoming increasingly popular as homeowners look for ways to increase their living space or generate rental income. However, these small dwellings can be notoriously difficult to keep energy-efficient. With rising energy costs and growing concerns about the environment, it’s more important than ever to make sure your granny flat is as eco-friendly as possible. Here are some tips to get you started.


One of the most effective ways to make your granny flat more energy-efficient is to improve its insulation. Without adequate insulation, your granny flat will lose heat in the winter and gain heat in the summer, making it less comfortable and more expensive to heat and cool.

There are several types of insulation available, including batts, blown-in, and spray foam. The right type for your granny flat will depend on factors like your budget, the age of your home, and the climate in your area. A professional insulation contractor can help you determine the best insulation for your needs.


Windows are another major source of energy loss in granny flats. Older windows may be drafty or have single-pane glass, which allows heat to escape in the winter and enter in the summer. Upgrading to energy-efficient windows can significantly reduce your energy bills and make your home more comfortable year-round.

Look for windows with a low U-factor and high R-value, which measure how well the window insulates against heat transfer. Energy Star-certified windows are a good choice for their energy efficiency and quality.


Lighting can account for up to 10% of a home’s energy usage, so it’s important to choose energy-efficient lighting options for your granny flat. LED bulbs are a great choice because they use up to 80% less energy than traditional incandescent bulbs and last much longer.

In addition to using energy-efficient bulbs, consider installing motion sensors or timers to ensure lights are only on when they’re needed. This can save you money on your energy bills and reduce your environmental impact.


Older appliances can be major energy hogs, so it’s worth investing in newer, energy-efficient models for your granny flat. Look for appliances with the Energy Star label, which indicates they meet strict energy efficiency guidelines set by the US Environmental Protection Agency.

Some appliances to consider upgrading include your refrigerator, washing machine, and dishwasher. While these upgrades may seem expensive upfront, they can save you money in the long run through reduced energy usage.


Heating and cooling account for the majority of a home’s energy usage, so it’s important to have an efficient HVAC system in your granny flat. If your current system is old or inefficient, it may be worth upgrading to a newer model.

Look for HVAC systems with a high SEER rating (for air conditioners) or AFUE rating (for furnaces) to ensure maximum efficiency. Regular maintenance, such as replacing filters and cleaning ducts, can also improve the efficiency of your HVAC system.


How much can I save by making my granny flat more energy-efficient?

The amount you can save on your energy bills will depend on several factors, including the size of your home, the climate in your area, and your current energy usage. However, studies have shown that energy-efficient upgrades can lead to significant savings over time.

Are there any tax incentives for making my granny flat more energy-efficient?

Yes! The federal government offers tax credits for certain energy-efficient upgrades, such as installing new windows or upgrading your HVAC system. Check with a tax professional or visit to learn more.

Can I make my granny flat more energy-efficient without spending a lot of money?

Yes! There are several low-cost or no-cost ways to improve the energy efficiency of your home, such as sealing air leaks and using energy-efficient lighting. Talk to an energy auditor or visit for more tips.

What’s the most important thing I can do to make my granny flat more energy-efficient?

Improving insulation is one of the most effective ways to make your granny flat more energy-efficient. Without adequate insulation, your home will lose heat in the winter and gain heat in the summer, making it less comfortable and more expensive to heat and cool.

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