原创 Hot and bothered these days...

When I'm at home I generally want the temperature to be about 70F in the day (68F at night). At least I think I do, because these are the readings I grew to know and love with the old thermostat that controlled our heating and air conditioning system.

Sadly though, a few days ago that old thermostat went a bit "wonky" – the liquid crystal display failed to the extent that you couldn't decipher what information it was trying to impart, so I called my heating and air conditioning guy, Olan, and had it replaced.

Everything seemed to be fine at first, but it didn't take long after Olan had left before I started to realize that things were not quite as I had expected. Now, if the thermostat is reading 70F I feel really cold – it has to be displaying 74F before it feels the way I like it. I was going to call Olan and tell him that the new thermostat was having problems... but then it struck me that this new one may be accurate and it could be that the old one was at fault. Hmmm...

So, my first move was to trundle round to my local pharmacy. When I was a kid you could pick up mercury thermometers very cheaply (we didn't know they were toxic). Unfortunately, the only units they had on offer were geared up to being placed under your tongue (well, that was one option) and taking your temperature, which wasn't quite what I was looking for.

Next, I wandered round to my local home improvement mega-store. The only thermometers they have are intended to go outside the house so you can sit in the garden complaining to each other how hot it is, but at least they cover the appropriate range.

The store had a variety of different types available for my delectation and delight. The cheap ones (a couple of dollars) were based on some type of liquid and looked a bit like the old mercury products of my youth. Then there were products based on a metallic spring that cost a few dollars more. (There were also digital versions that cost more again, but my thermostat is digital and I don't trust it, so I decided to opt for one of the more traditional technologies).

An example metallic-spring-based analog thermometer

The thing is that I had picked one of the cheap-and-cheerful liquid-based units up – and was about to walk off with it – when I noticed that its reading didn't match that of the next unit in the rack. I think the one in my hand said 60F while the one on the rack was hovering around 64F. So I started rooting through the rack. Believe it or not, every single thermometer gave a different @#$%$ reading. Similarly for the metallic spring-based units (I couldn't see the values on the digital units).

My temporary workaround solution was to jot down a list of the different temperatures shown by all of the units on display (I think there were about 23 or so). I then averaged out all of the readings and selected the thermometer that came closest to this average value.

When I returned home, I stood this thermometer on a table under the main thermostat – left things to settle down for an hour or so – and then checked to discover that the liquid thermometer shows around 68.5F when the digital thermostat reads 74F.

Arrggghhh! If the liquid thermometer had showed 70F to 74F on the thermostat, then I would have felt totally vindicated, but the fact that it shows 68.5F has thrown me off the other way. Was the old thermostat also in error? Are all three units lying to me?

In fact this raises several issues. First and foremost, how do I go about definitively measuring the temperature in my house in the vicinity of the thermostat in order to decide exactly what's going on?

The other big issue is that I am shocked and horrified (well, at least a tad surprised) by the fact that something as simple as measuring the temperature is proving to be so problematical. I guess that if you had asked me a couple of days ago, I would have been under the assumption that modern manufacturing processes have been so perfected that something like a box of thermometers would have all given much the same reading. I could accept some small error due to tolerance, like say half a degree (although I would have preferred a quarter of a degree), but finding a range of readings from 60F to 67F in a rack of thermometers just blows me away.

Now I'm wondering what other instruments are lying to me?