New winter carpet

Winter has again seen us working at staying warm without turning on heaters.

 

Our winter floor covering had been getting increasingly threadbare. Last year we insulated it with a layer of padding underneath, cut from the base of a single bed that was on its way out (having been with me for about 30 years). This layer did help, but it covered only part of the area, and didn't address the holes developing in the old rug. When friends offered us a replacement rug that they were disposing of we jumped at the chance to upgrade.

With a nice thick layer to catch morning sun warmth and insulate us from the cold of the tile floor, we have been enjoying playing on the lounge floor with no additional heating. 

We also added carpet offcuts under both the lego table (the central item in our living space) and the dining area, which have added to the winter floor insulation. The thick white one under the lego table also cries out for cubbies to be made under there - a call to which the children readily respond. 

A few years back we had a go at carpet offcuts under the dining table. After one season they got shabby and didn't return the next year. It is a challenge storing them through summer. Hopefully we can manage it this year, but if not it is possible we could just get a fresh round of carpet pieces each autumn, as they are destined for waste anyway.

Initial Time:  ten minutes of lifting furniture to lay the rugs/ carpet pieces

Initial Cost: zero - carpet offcuts are free behind the carpet store; the lounge rug was a second-hand gift.

Ongoing time or cost commitment: ten minutes when the weather warms to take up and store floor coverings. If satisfactory storage for the carpet offcuts can't be found, there will be time next year making a trip to pick up some more from the carpet store - no more than half an hour, as it is not a long way to go.

Impact: Our most recent electricity bill, for May and June, showed we had used an average of 6.2 units (kWh) of energy per day, down from 6.6 units per day for the same period last year and 8 units per day the year before (but the previous three years we were in the 5.8 to 6.1 range, so it has not been all improvement!). By comparison, the average household use in our neighbourhood is 11.9 units a day, and 'similar houses' record an average of 13.1 units.

We have turned on the heating (reverse cycle airconditioner) I think twice so far this winter, each time for about an hour to take the chill off. Carpets are just one of the range of measures we take to warm ourselves without using electricity (see also May and August 2014 posts)

He has mittens on because they were new and he was enjoying them, not because the room was freezing. He was also bare foot when I took this picture.

Keep calm and shade everything

We are setting records for hot weather again in Perth this week, so it seems a good time to share this summer's improvements to our shading.

Externally, our home is shaded by vegetation where possible, shade cloth protecting most glass areas, and an ad hoc combination including: foam mats in a window, a shed against a western wall, folded trestle table leaning against another wall and an assortment of things hanging on the clothesline. Internally, we have experimented with many ways to create an insulating layer in our windows, to keep the day's heat out. Most of these I have previously discussed here or here: towels, old painting canvas, mattress, cardboard boxes, cushions, styrofoam cooler boxes... All of these are good, but this year we are onto something I think is easier and potentially more effective: corflute board.

For those unfamiliar, corflute is a 'twin wall polypropylene sheet'. Because it has a ripple between its two surfaces it creates a layer of trapped air - exactly what you want for insulation. However, corflute allows some light through (more than, say, a mattress or cardboard box in the window), meaning the house can be not quite such a cave on hot days - although, as most of our recycled corflute came coloured black on one side, we are not benefitting quite so much from this property.

We now put corflute up inside five windows on hot days, and have installed a 'permanent' summer panel of corflute across half of the over-exposed glass sliding doors to the southwest facing laundry. The loungeroom window panels, being about two-thirds window height, leave a 'clerestory' window space, shaded by the small eaves, which allows a bright naturally-lit room.

Initial Time: There was no set-up time besides sourcing the corflute, which we did within other activities. We did make a kids' art activity out of decorating the panels for the lounge window, as I didn't want to live with the brand names from their previous life, but that was optional and fun.  

Initial Cost: Zero. We picked up our first panel of corflute at REmida, the wonderful centre in West Perth that recycles industrial discards for use by schools, community groups, artists and individuals. The rest came via Tyson's dad, a retired engineer, who had a bunch lying around from disused signage picked up on construction sites. If you have to buy them, corflute panels roughly this size cost about $4-$5 each.

Ongoing time or cost commitment: Every day, a few minutes at each end of the day to put the shades up and take them down. 

Impact: A southwest facing vertical surface in Perth in summer receives approximately 3kWh of energy per square metre per day. Its best to shade on the outside, so the heat doesn't get in at all, but providing an insulating layer inside windows slows the rate that heat energy gets into the room, and reflects quite a lot of it back through the glass. Once the heat is inside your house, you have to either live with it or remove it. The latter requires electricity, and lots of it.

As I write, well after dark, it is hot and still, the end of our fourth consecutive day over 40°C (104°F). We've equalled the record for days-over-forty (set in 1933) and if it hits 40°C again tomorrow we will have a new record. Perth is a funny place - although we are all wilting, there is also a slightly defiant 'bring it on' mentality. We wouldn't mind one more extreme day if it meant we got to Break A Record. 

Here at our house, we are feeling pretty good about how little we have used the aircon in the past four days: so far only for three or four hours total. We've done most of the things I talked about last time we had a record hot week, in addition to all our passive cooling measures. The corflute board has been up each day and is working a treat to keep out much of the 3+kWh we've been receiving. We also replaced our big rear shadecloth at the start of summer (the eight-year-old one finally perished) and the new shade has a higher block-out rating (90%). If it wasn't for the hot nights and lack of overnight breezes to refresh the house we probably wouldn't have needed the aircon at all.

Pelmets and Pantry doors

I'm writing about passive cooling again. Its still summer here and so we continue working on ways to keep the house cool without using electricity. The latest commitments: a make-shift pelmet, and a commitment to close the doors of built-in cupboards.

Pelmets are those ugly wooden box-covers that go around the top of a curtained window, gathering dust and trinkets. I always considered them a bit of interior decorating vanity, but thanks to Tyson's training in home sustainability I was made aware of their insulating value. Pelmets prevent convection currents pouring hot air into the room. The air in the gap between curtains and glass heats up and rises. If there is a gap at the top of the curtains, this hot air escapes into the room even though the curtains are shut.

Real pelmets are not a feasible addition for renters, but a rolled up blanket works nearly as well. I was inspired by my Mum, who has bath towels along the top of her curtains, and she in turn was inspired by her sister, who uses pool noodles.

And the cupboard doors... two wardrobes have back walls that are external, baked with morning sun. Closing the doors helps keep that heat in the cupboard and out of the bedrooms. The other built-in cupboards heat up less dramatically, but they don't need to be cooled (or heated, in winter) so keeping doors closed reduces the quantity of air we are trying to temperature-manage. The pantry is directly opposite the airconditioner. When we do run the aircon, it is a complete waste of energy to leave the pantry door open and cool all our tins and packets!

Apparently some homes do not have roof insulation above their built in cupboards. If you have insulating bats it might be worth checking your roof space. We have blow-in insulation and that is less discriminate about what it covers.

Initial Time: Blanket pelment: about three minutes. Cupboard doors: a few seconds each morning as part of the roughly five-minute circle round the house to close up for a hot day.

Initial Cost: Zero.

Ongoing time or cost commitment: Zero cost. The blanket doesn't need to be removed to open or close curtains but it does start to sag and needs a minute or two every few days to pull it back up into position.

Impact: The one room that has curtains (everywhere else has blinds) is keeping cooler - and darker! - since we installed the blanket 'pelmet'. Its the master bedroom, and I have had cool afternoon sleeps in there recently on some very hot days.

I don't have a way to measure the impact of closing cupboard doors, but I know at the end of a heat wave, I leave the cupboards open through the night to cool down. Otherwise when I next open them a wave of hot air comes out, saved carefully behind the closed doors, which suggests closing the doors does have some impact on overall air temperature.

April 2010 - Pipe Insulation

Even the most efficient water heating systems still face the problem of water cooling in the pipes before it reaches the point of use. We collect about half a bucket of cold water in our shower before the hot gets there, and a substantial amount of cold water goes down the kitchen sink while waiting for it to warm up also. This month we decided to insulate the water pipes where we could get to them.

Initial Time: 15 minutes to cut and fit insulation piping on outside pipes. Tyson got into the roof space to see if the pipes were exposed there also, which was an additional time commitment, but after insulating a section of gas pipe by mistake he concluded that the hot water pipes are not in the roof cavity, so I won't count his roof crawling time here.


Initial Cost: We were given four metres of insulation piping free as a promotion from Environment House and bought some extra from Bunnings - $6.89 for a two metre section.


Ongoing time or cost commitment: zero.

Impact: We still run a lot of cold water in the shower before the hot kicks in, as it is on the other side of the house to the water heater. Its hard to say whether the temperature is warmer once it gets going, as we did this right on the change of season so the pipes are contesting with colder weather than before we made the change. In the kitchen, which is closer to the water heater, we have noticed that the water appears to have less cold delay, and is hotter when it arrives.  This is definitely true in the laundry, which is directly through the wall from the water heater.

I can't give a precise measure on any of that, though.

Update: Tyson has put some measurements in the comments. 

Also I think I should emphasise that even when you are not using any hot water, the outlet pipe from a storage hot water system acts as a kind of wick, drawing heat out of the storage tank. Insulating the pipes not only keeps the water we are using hotter, it also keeps the water waiting in the tank hotter.