Category Archives: House and Garden

Building a sunroom: Our temple to the sun god

Our house, like many old houses in this part of Australia was not designed well for the local climate. In an area that is quite cool, the house was built with minimal windows facing the northern sun. Australian’s have a love affair with verandas and generally that’s ok because most of them live where it is usually hot. What is needed here is passive solar design.

Frosty morning

This is the sort of cold we get here. It can drop below freezing before we go to bed, but it is often followed with a sunny day.

We found we did not use the veranda often because it was either too hot, too cold, too windy, too many flies buzzing about, too many vicious mosquitoes or there was just too many other things to do. It was just a waste of space that required regular maintenance. We decided to convert it into a sunroom and become lovers of the sun.

The build

I won’t go into too much detail about the build as I’m not a builder and this post is really about the benefits of passive solar design.

This is what it looked like before we started

The build started with help from my father to replace the floor. Then I ordered a lot of windows and a glass door.

A massive hail storm hit the town before our windows were built. Many windows around town were smashed and repairing those was the top priority for glaziers so our windows were delayed until around the time our first baby was born. This added some extra pressure at a time when we didn’t really need it.

Once the windows and doors were in place I removed an existing window between the kitchen and the new sunroom and converted it into a doorway. Next job was fastening some plasterboard over the old weatherboards and hiring a plasterer to finish it off. We got an electrician to install lights and a power point and then we painted the walls and bought and carpet and had that installed. On the exterior we had to add a row of brickwork around below the windows and a small section of tiling at the front door.

The end result. Notice the removable awning on the western side to prevent overheating in summer

Costs

All up it cost around $10 000. That was 15 years ago, so these prices are out of date. The windows and glass front door were the biggest cost at $7000.  We needed 100 meters of fabric for the curtains and our family helped by sewing these. Even so, with curtain rods the total for that was around $1000. The final $2000 went on flooring, carpet, electrician, plasterer and paint.

How good is it?

Aesthetically it is ok. You won’t read about it in Home Beautiful. It’s not going to win any design awards. From a practical viewpoint it’s great. A lot of projects that I have done have not been successful, but this was more successful than I imagined it would be. It went from the least used area of the house to one of the most used. Visitors gravitate to it and are usually surprised at how warm it is inside.

Inside. The original ghastly pink colour I chose for the internal walls has been replaced with stone finish paint.

Some people are surprised that a sunroom will significantly warm a house although they are not surprised at how hot the interior of a car can get parked in the sun and there really is not that much difference between the two. There is roughly 1KW energy per square metre from the sun, or so I beleive. About 14 square metres of sunshine enters through the front windows at midday in winter, so I think that we are getting about 14KW of energy. It doesn’t all get retained as heat as some is reflected back out, but it’s still substantial.

We have a wood heater that is very good, but it only outputs around 10KW of heat. We have a reverse cycle air conditioner as well and it is ok, but it only outputs around 6KW of heat. The sunroom makes a far bigger contribution to our heating than either of these. It only takes a cloudy day to be reminded of this, although even when it is cloudy there is often some warmth in the sunroom. It is now our main heating source with the wood heater only required on cold nights and the reverse cycle usually only on cool mornings when the wood heater has not been used overnight.

During the day it is often 10 – 15°C warmer inside the sunroom than it is outside. It’s not uncommon for it to get up to 28°C (82°F) inside when it is only 13°C (55°F) outside. We usually wear tee shirts in winter and still feel very warm. Parts of the house further away from the sunroom are not as hot as that, but generally they reach very pleasant temperatures.

28.4 degrees celcius

It is was 11°C (52°F) outside when this picture was taken. This is a measurement of the wall temperature in an area that has not been in direct sunlight (28°C – 82°F)

It has changed our house from a cold old house into a warm, light and pleasant place. If you live in a cool climate and you get the opportunity to visit a house that uses passive solar heating then see what it’s like. Using “alternative” technology does not have to be inferior – it can be superior.

Tips

When you have as many single glazed regular glass windows as we do it doesn’t seem to matter if curtains have thermal backing or not, or even if you draw them closed or not, it is still going to get cold overnight. Maybe the temperature will not drop quite as quick but it seems to be just as cold by morning. We overcame this by shutting the sunroom off from the rest of the house at night.

These doors were added later, They are a important part of the design, preventing heat loss at night and also to keep up heat during hot summer days.

Windows on the northern side (in the southern hemisphere) are good. The sun shines in during winter, but not in summer. Windows on the west or possibly the east are not as good. We place a temporary awning above the western windows during summer to reduce the sunshine entering the house otherwise the house would be unbearably hot.

A concrete floor with a high thermal mass should absorb and store heat during the day and release it during the night. That was too difficult for me to do, so we don’t get that benefit.

The sun is harsh on carpet, paint and furniture. We currently have three chairs. We deliberately use old ones. Only one was purchased new, one is second hand and the other came from our local dump shop. Covering them will lengthen their life, otherwise they will not last many years.

Cleaning the house windows became a big job.

To work well the room needs to receive plenty of sunshine. A cloudy climate of shading from trees and buildings will make a vast difference.

Other articles

This is the second post about solar projects we have tried. I have already covered using waste heat from the roof to warm our house. Still to come is our experience with solar hot water heating and grid connect solar electricity systems.

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The Possum: A cute but challenging animal to live with

The Possum is a mammal that is native to Australia, New Guinea, and Sulawesi. There are many species but the one most common in our area is the brushtail possum. They are nocturnal so many people are unaware of them except for hearing the spooky sounds they make, the crashing noises on the roof at night and finding parts of their vegetable garden have disappeared.

They make a sound that is truly spooky as this Youtube video by tomstorey shows.

They often become quite game, some say they can become tame but I’m not too sure of that. They are fun to watch but can drive a home owner or gardener to despair. And oh, they are a protected species in Australia.

Over the years there have been quite a few living around our yard. Our house started life as a weatherboard house but was later given a brick veneer. Bricklayers simply built a layer of bricks on a concrete footing up around the house. This process left a gap between the weatherboards and the bricks. When we moved in there was no door protecting access under the house. This provided easy access for possums but this wasn’t obvious to us until one day my wife said, “Why is the kitchen light on…. It seems to be very dim. Look there is water running out of it.” Heading up into the ceiling we discovered a possum had knocked the top of the header tank for the hot water system which fell into the tank leaving it sitting at an angle and holding the float down. Water was spraying out onto the ceiling and draining down through the kitchen light. The culprit was asleep on top of the warm hot water system. It took us a while to figure out how it got up there and from then on we knew these things could be a problem.

Since then we have secured the house fairly well and we have lived in relative harmony, but they have continued to make themselves known. One learned to use the cat door and just after sunset each night would head in through the cat door to have a look around. We thought we had it locked out but found that it was sleeping up above the wall oven in the kitchen.

We collect rain water from our roof that is stored in a couple of tanks that is used for drinking and washing. So it was not pleasing to see a possum sleeping in the main junction box that connects the guttering from the two sections of the roof.

Possum in guttering

Possum camping in the juntion box of the guttering system

Another managed to get trapped in our shed one night. We didn’t immediately notice the possum but the trail of destruction was obvious as was the urine. I found the possum and being oblivious to the dangers of trying to handle one, I put on large welder’s gloves and tried to pick it up. Eventually I grabbed it by the tail. They can hang by their tail and I knew this wouldn’t harm it. What I didn’t know was that they can swing around and climb up your arm. We both got away with minor injuries and the most painful part for me was the tetnus injection that afterwards.

I have since learned that they are territorial, so we formed a plan to build a few houses for them. Those that moved into a house should keep newcomers at bay.

Possum in a possum house

A current resident

In practice this has only been partially successful. While they may be territorial, either their territory is quite small or they are willing to overcome their preference for space and live close to one another to be near food. Also, it automatically guarantees that there will always be some around constantly trying to attack the vegetable garden. The simplest solution we have found to protect the garden is a floppy fence that is difficult for them to climb.

We have usually had three possum houses at any given time in our yard and surprisingly three times we have had a swarm of bees take over a house when it was temporarily vacant.

Beehive in an olde possum box

A swarm of bees moved in while the box was vacant

Last year they must have had a good breeding season and we ended up with a couple of youngsters looking for a home. One decided that our wood heater was the place to sleep – after all from there he could peer out through the glass and watch TV.

Possum peering through the glass of a wood heater

Is that something in there?

To get in, it has to go up onto the roof, climb up over 1.5m of the outside of the chimney to get to the top, squeeze under the chimney hat and then descend 6m of 15cm diameter vertical tube into the heater. Fortunately it has decided to move out so we can light our fire on cold nights.

Door of the heater open showing a possum sitting inside

Hello possum