What’s wrong with water softeners?

Cambridge has hard water and it scales up our appliances. Some of them we can clean with a bit of effort, but some are not so easy. You can clean the heating element in your kettle just by soaking in hot dilute vinegar – but getting at the heat exchanger in your hot water cylinder is a tricky job. The obvious answer is a water softener. 

There are two problems.

1. Water softeners use extra water and we are already water stressed in this area.
2. Water softeners use a lot of salt and this is bad for the environment. It has to go somewhere: usually it ends up in our rivers.

How bad is this and what can we do about it?

Learnings from monitoring the solar hot water system

For reasons too complicated to explain (best summarised – if I was you I would not start from here) my beloved has implemented a controller for our solar thermal pump. This is for a solar thermal panel, rather than a solar electricity panel. The pump circulates hot water (with glycol) from the panel to the hot water cylinder and back. Knowing my love of data he added some monitoring into this system and we have been poring over the charts. Here is one from a reasonably sunny day.

Monitored temperatures on a sunny day (times in GMT)

Travel emissions per hour

How do you think of travel distances in your head? People often think in terms of the time taken to get there rather than the actual distance. One hour (each way) is not unusual for regular commute by car and for a weekend excursion you might think three hours was reasonable. By air you can get quite a long way in three hours. Here I compare GHG emissions for various travel modes by km and by hour. 

This post was inspired by some much prettier graphics from the Visual Capitalist showing emissions per km. I have come to think that metric is positively misleading. 

How to grow climate friendly food at home

Were you as shocked as I was to hear that growing your own food at home has six times the GHG emissions as conventional agriculture? Surely it does not have to be like this? I looked at the study behind the news [1]. (It came out in January and I do not understand why it has hit the news again now.) The good news is, the main sources of emissions from home grown produce are easily avoided, with a bit of care. 

Compost heaps were one of the main sources of GHG emissions from urban gardens - but good practice can minimise this.

Temperatures in my youth and now

How have external temperatures changed in my lifetime? I have been playing with graphs that show current X (e.g. temperature) as a line versus historic X as typical ranges. Here is one showing temperature in East Anglia in my youth (age 0 to 21) versus the last six whole years. The shaded areas show the range of temperatures seen from 1963 to 1984, with green and blue being below the median while orange and red are above the median. The temperatures are the average, including overnight, The maximum temperature chart actually looks much the same only shifted up a bit.

Mean temperatures by month in East Anglia from 2018 through 2023, versus typical temperatures (shaded) from 1963 to 1984. Click to see this enlarged.

A whole street of heat pumps - noise levels

Heat pumps make noises, of course they do. The question is, will their noise be a nuisance if every house on the street has one? The short answer is - not usually. Here I explain why we are not disturbed by ours, and why a whole street of heat pumps does not sound much louder than a couple. In urban areas, other noises are much more noticeable. In rural areas, you might be disturbed by yours but not so much your neighbour's.

Rainwater harvesting: dammed by regulation

For the whole of the East of England water supply is an increasing problem. Here in Cambridge we need to reduce the amount we take from our aquifers by about half in order to protect the chalk streams. This will be achieved with a combination of reducing leakage, reducing demand and increasing supply (by building large reservoirs). One way to reduce demand is to harvest rainwater for use where it does not have to be drinking quality, such as flushing toilets. 

Eddington in North West Cambridge has a rainwater harvesting system for 3000 homes, the largest in the country. It is often cited as an exemplar for water saving, with every home having two supplies: one from rainwater (non-potable) for use in the garden, in the washing machine and flushing the loo alongside the one from the mains for everything else. As I recall, the pipework has different colours. The rainwater is stored in a rather beautiful lake and is fairly clean but not as clean as the water we get from the chalk aquifer; there is equipment for basic treatment on site. The problem is, the rainwater harvesting supply has never been commissioned due to concerns from the Drinking Water Inspectorate (DWI). 

 

Brook Leys Lake at Eddington – stores rainwater for supply to homes, but not commissioned for use.