June 30, 2017: Case Study – Holiday House Energy Upgrade

I recently had the pleasure of being invited to perform an energy audit on a holiday house in one of the many gorgeous villages on the south coast of NSW. The house in question is owned by a family from Canberra. The children are all adults now and the ten-year goal of the owners is to retire to the South Coast and live in the house permanently. In the meantime it is rented out as a holiday house with the income generated to be used to pay for the upgrades so that, by the time the couple retire, the house will be comfortable, energy-efficient, low-maintenance and ready to for them to retire to a life of relaxation in a beautiful part of the world. But before that happens, the house has some issues that need to be addressed.

In a case like this, before going to examine the house, the first thing I do is take a look at it from my private satellite… ok, it’s Google’s satellite and it’s fairly public but it’s still very helpful.

Image source: Google Earth

Image source: Google Earth

To protect the owner’s privacy I can’t show you where it is but I can tell you that it is in an excellent location. The site slopes north and is within easy walking distance of the beach and shops. It’s a perfect spot for a holiday (or a retirement for that matter). However, one look at the satellite image above reveals some very telling information about the house, such as…

  • There are tall trees shading the north and east sides of the house and the east side of the roof. Google Earth tells me that the image was taken on the 16th of August so, clearly, shading from these trees is limiting the solar gain through the morning and the middle of the day in winter.
  • There are other trees on the south side of the house which are helping protect it from cold winter winds.
  • Most importantly, the house is very exposed to the West and North-west. This is likely to present a problem in summer because hot western sun is very hard to control. On the upside, the west side of the roof has excellent solar access for the possible addition of a solar power system.

So, armed with that information, I headed down the south coast to have a closer look (I know, it’s a tough job but someone’s got to do it, right?).

The two-storey west-facing wall of the house.

The two-storey west-facing wall of the house.

The first thing that struck me as I approached the house and which you can’t tell from the satellite image is that the house is two storeys. So the western wall which is exposed to the hot afternoon summer sun is twice as big and generating twice the amount of heat gain. The other thing you can’t tell from Google Earth is that, underneath those trees on the north side of the house is a beautiful, shady deck with a charming view through the tree trunks to the ocean. It was immediately obvious that cutting those trees down was not going to be an option.

The owners were there on a family holiday and we had a good chat over tea at the dining table. This revealed the following issues that they are hoping to address:

  1. The upstairs bedrooms get very hot in the summer and lack effective cross-ventilation.
  2. The west wall gets too hot to touch at times in the summer.
  3. In bushfire times the house has to be kept closed due to asthma issues and can become unbearably hot.
  4. The house is drafty in winter.

After a nice cup of tea, I did a thorough inspection of the house including climbing up on the roof, examining the structure in detail, looking closely at the areas under the house and inspecting the whole lot with an infrared camera. This revealed the following issues:

  • The biggest problem is (not surprisingly) the west wall. The lower part of the wall is somewhat insulated but the upper section not at all so heat was radiating through that wall like you wouldn’t believe. Unfortunately my IR camera wasn’t letting me take pictures that day so you’ll have to take my word for it… it was lit up like a Christmas tree.
  • The roof was not too bad by comparison but may need additional insulation in the future.
  • There are good, north facing windows that are currently being shaded and other’s that could use some shade in the summer time.
  • There is thermal mass on the ground floor that can be utilised to help keep the house warm in winter and cool in summer. Plus…
  • The house is potentially susceptible to termite invasion.
  • There is a moisture/rot problem developing along the east wall.
  • The gutters need to be kept clear of leaves.
  • And a downpipe at the south end of the west wall is not properly connected.

I won’t go into all the details here (if you would like to read the full report I presented to the owners at the end of my inspection you can find it by clicking here) but, in short I made a list of recommendations that included:

  1. Some simple actions that they can take right away to reduce the likelihood of a termite problem and to improve the general durability.
  2. Other low-or-no cost things they can do to help keep the house warm in winter and cool in summer. Things likeremoving shade cloths in winter, adding more shade in summer or moving furniture so that the sun shines on the floor slab in winter… that sort of thing.
  3. Prioritising the upgrade of the west wall so that it is properly insulated and air-sealed and windows are correctly placed to allow cross ventilation through the upstairs bedrooms in summer.
  4. Correcting a minor rot problem that is developing along the east wall and upgrading that wall as well (eventually all of the walls will get the same treatment).
  5. Installing a high-efficiency reverse-cycle air-conditioning unit. This will be particularly helpful on those bushfire days when opening the house for ventilation is not an option for the asthma sufferers.
  6. Upgrading the roof insulation if necessary.
  7. Installing a solar power system.
  8. Insulating and air-sealing under the exposed parts of the floor (this will help a lot with the draftiness in the house in winter).
  9. Replacing the existing electric element water heaters with heat pumps timed to run off the solar power system.
  10. Utilising energy efficient cooking equipment like slow-cookers, microwaves and induction cooktops.
  11. And, in the process of doing all of the above, allowing for the future addition of batteries and electric cars to the energy mix.

Basically I tried to provide them with a road map for how to move forward over the next ten or so years so that, when retirement time comes around, the house is ready for them to relax and be comfortable with manageable energy bills and low maintenance.

Since the house is already paid for, it’s a perfect opportunity for them to use the income produced by holiday rentals to fund the upgrades they want and make them tax-deductible in the process. This is very smart financial planning.

Plus there is a further benefit to upgrading a holiday house which is not available to most long-term rental landlords. Under most long-term leases, the electricity and/or gas bills are in the tenants name. Because the landlord doesn’t pay the energy bills, there is little or no incentive for him or her to spend money on upgrading the energy performance of the house. This leaves the tenant either uncomfortably hot and cold or stuck paying very high energy bills to keep the house comfortable.

In a holiday rental, the bills are in the landlord’s name so any improvements to the energy performance of the house will result in reduced costs and increased cashflow to the landlord, not to mention happier tenants because the house is more comfortable. This gives the landlord a big incentive to spend money on upgrades that also happen to reduce the carbon footprint of the house as well.

I’ll continue to advise the owners as this project moves ahead and I look forward to seeing how it all works out for them and reporting on the progress as the improvements happen over the coming years.

A sneak peak at the new deck and awning roof.

A sneak peak at the new deck and awning roof.

Meanwhile, I’m still plugging away at the energy retrofit of the cottage next to the Greeny Flat. Lately I’ve been working on adding a shade awning and deck on the west side of the house. This is nearly finished and I’ll put together another little video when it’s done. Then we’ll be installing a rainwater tank and a slow-combustion wood stove…. so stay tuned.

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