Mechanical ventilation - to use in summer or not?

Mechanical ventilation with heat recovery is great for the cooler months, you get that fresh air feel without having to open windows and without losing all that heat you've built up with your central heating.

The question is though, should you leave it on during the summer or should you rely on opening windows? If you leave it on then it is using energy to ventilate your home, although with a summer bypass function there will be no heat recovery. The other advantages include not having insects coming in to bite at night or buzz around your food, and it reduces the disturbance from the inevitable increased noise in summer - planes flying, children playing, barbeques in the garden.

But it does use energy and you could just open the windows to create air movement and a cooling effect.

The first year we had our system we kept windows shut and the MVHR switched on - we knew the horrors of a fly infestation and didn't want a repeat! In a hot spell it was quite hot in the house, but then it would have been hot if we opened the windows; the MVHR certainly didn't act like an air conditioner.

This year we are using windows and blinds during day to keep sun out and allow fresh air in; we're putting up with daytime insects. Once there are lights on in the evening we close all the windows and use the MVHR to ventilate the house and that's successfully kept away the mosquito bites!

We try to keep our electricity bills down in other ways, i.e. nothing is left on standby, broadband is turned off when we're not using it, we use a laptop rather than a pc and this is put on standby if not in use for more than 10 minutes and turned off at other times when not being used.

So maybe the MVHR is our electricity indulgence, along with the fridge/freezer and phone. However, used intelligently we feel it contributes to good ventilation of our home without excessive energy use.

Has anyone else out there had experience of using these systems in their own home?

Clever use of blinds and curtains

Curtains and blinds can help improve the thermal performance of your house - more information. Since having ours installed we have learnt a lot about their effectiveness.

The first big shock was the effect of having our house decorated over the period early October up until Christmas last year. We had approached the decorator in May, but that was the best time we could get. Anyway we didn't have any curtains or blinds at our downstairs windows for that whole period; also doors were left open quite a lot during the day and on top of that we had snow from November. All of that led to a massive increase in our use of gas - it came as quite a surprise.

We have noticed some real benefits of our blinds since then. We have a Luxaflex Duette insulating blind on our patio doors. This stops quite a lot of the cold air coming through that large expanse of glass - and it does come through despite being double-glazed. If we raised the blind first thing in the morning we could feel that cold air trapped between the blind and the window and that was then coming into the room. So what we've been doing is waiting for the morning sun to warm up that layer of air, then we open the blind. We can then make the most of the solar gain from the sun coming in through the glass and warming the room.

During very cold weather we often left the blind closed all day as it gives the room a nice light feel even when closed and it's kept the room that bit warmer. At night we add thermally lined curtains to keep the house even more cosy.

Also when it is hot or too sunny we've used the blind to stop too much heat coming into the house. Glaring sun can be excluded by partially closing the blind; too much heat coming in can be prevented by closing the blind altogether to prevent that solar gain. The room is still nice and light but it is a cool oasis when it's been really hot outside. When it is cooler outside at night we've raised the blind to reduce temperatures indoors.

We have a north window that has a Luxaflex Architella blind, which must be about the most insulating blind on the market. We keep it firmly closed in the winter, which definitely reduces the icy draught coming down our stairs! In hot weather we can open it to help us lose some of the heat indoors.

We are seriously thinking about having these blinds in other parts of the house as we are so pleased with how they have worked. If we have another cold winter we hope to also notice the difference in our gas bills - it's clearly not enough just to have double-glazing.

Solar Panels working - it's great

Since we've had the sensor replaced our solar panels seem to be working better than before. As well as being replaced the sensor was also put in a slightly different position, so maybe that's why.

Between May 7 and September 24 2009 the panels were working for 246 hours total, about 1 hour 45 minutes each day on average. Between 18 May and today, 28 May 2010, they have operated for 56 hours, an average of about 5 hours 36 minutes a day. In addition, the water has been getting up to maximum temperature and has been working in clould as well as sunshine.

If it goes on like this then our gas bills will be even lower, which is great news.

We just need to make sure that squirrels/other wildlife don't take a fancy to the cable again!

The Mystery of the Solar Panel Sensor

I was saying 2 days ago that the sensor had broken on our solar hot water system. Well, the guys have now been out to fix it and the problem wasn't the sensor, it was our wildlife!

The cable had been chewed through and the sensor taken away. We don't know who the culprit was, but grey squirrel is at the top of the list of suspects. But magpies or jackdaws, with their liking for shiny objects, might be possibles, although it would be harder for them to break through the cable.

The squirrels have a track reocrd too! When the power to the garage was linked to the house by a cable along the top of the boundary fence they chewed through that wire and broke the connection. Every so often there would be a bright flash outside, like someone taking a flash photo, it took ages to work out what was going on. Presumably each flash was an electric shock for a squirrel, but it happened more than once so they weren't easily put off!

Let's hope that we don't have a repeat with the solar hot water sensor. This time black cable has been used instead of white and the sensor has been tucked away a bit more.

I'll keep you posted! I'd also be interested to know whether anyone has had the same problem - please let me know.
Carol Hawthorn

Bluebell Woods

Over the weekend we visited our local woods to see the bluebells in flower - they are a bit later here than in most places, but spectacular once they are in full bloom.

What struck me was that there were more people than usual in the woods and most of those had come to see and, in some cases, photograph the bluebells. Maybe some of these people only visit the woods at this one time of year. If so, they no doubt expect the woods to be still there and the bluebells to be in flower, which gives me hope as it means they care about the future of this patch of nature.

As long as there are sufficient people who care about these iconic sights in nature then maybe they won't disappear altogether. We need lots of people to care and to stick up for their local patch when it comes under threat, which means at other times they should be able to enjoy it. In the meantime though we need our local Wildlife Trusts, the Woodland Trust and the National Trust, etc to own and manage these sites, which means funds from subscriptions or grants, so that we can continue to take these places for granted.

Connected to the sun by solar hot water

The sensor has failed in our flat plate solar panels. This event has made me realise the effect on me of having solar panels to generate our hot water. I have become attuned to how they work, almost subconsciously noting what the sun is doing when and whether there's any need to boost the hot water using the gas boiler.

It's not a case of keeping a record, using data or even feeling the pipe connecting the panels and the tank. It's not a technical process, it's an awareness of the outdoor environment.

I hadn't realised it had happened until the panels weren't working. Even though I knew the panels weren't working I got caught out and found there was really cold water in the morning. I had based my decisions on use of the boiler on the amount of sun, completely forgetting the link had broken. Normally, with solar panels, there would still be hot water from the effect of yesterday's sun. However, without solar panels you have to use your boiler every day to get hot water, so it's in use throughout the summer when your space heating is turned off.

I am really looking forward to the new sensor being fitted so that I can get back into my solar cycle again. It's about more than the savings on our gas bills, which incidentally are noticeable following installation of the panels. Payback on the capital outlay may take time, but our bills now and into the future are lower, so worth doing.

We are losing our beautiful insects

Butterfly Conservation have serious concerns about the threats to butterflies and other insects. Almost a third of Europe's butterflies are in decline and nearly 1 in 10 species is threatened with extinction. The European Red List also shows that 14% of dragonflies and 11% of those beetles that rely on decaying wood are at risk of extinction. Loss of habitat is stated to be a cause, such as loss of traditionally farmed grasslands, woodlands and wetlands.

Loss of biodiversity I think is as important an issue as Climate Change. In fact the Rio Summit in 1992 put most emphasis on the biodiversity issue, I remember being at the Natural History Museum and hearing the scientists speak who had been at that summit. Natural ecosystems and the species within them are a vital life support system for the planet. These species and ecosystems are becoming fragmented and disappearing, perhaps without most of us noticing. But we really do not know what we are losing, just how these ecosytems support us in terms of air that we breathe, pollinating our crops, and probably in many ways we don't understand.

I think for our own wellbeing it is important to connect with the natural world around us, it makes us feel better and increases our awareness of what is going on. It's very easy in our culture to live in a virtual world, where what we see and hear through electronic media seems more real than what is outside our own door.

Just making our own garden a haven for wildlife can be very rewarding. A quick walk around my own garden can reveal slow worms, butterflies, signs of a hedghog or fox, a robin having a drink, the changes in the flowers. It is easy to grow the right plants, allow a few native species in odd corners, provide shelter and not be obsessively tidy so that wildlife can share your garden.