Heatmap of the month – cross sections, not cross colleagues

This months heat map is a bit of rarity – an example of what happens when you get HVAC right.

To get this impressive cross section of a London office our customers hung kittens on strings at several points along the ceiling. Each string had a number of kittens, spaced a meter apart, to give a vertical grid of temperature sensors.

The office is a converted Victorian industrial building, with a first floor and mezzanine. It houses about 80 employees for a professional services company, and keeps them at the right temperature with a comfort cooling system that delivers cold air through ducts at floor level.

So what are we looking at here? This is three days from July where the external temperature varied from 9°c to 25°c. Even though this office has a huge volume of open space and floor to ceiling in excess of 8 meters, the temperature on the first floor and mezzanine is well controlled. The mezzanine is a degree or two warmer, but rarely gets outside the comfort band.

Just to be controversial we’ve included a Saturday – and a hot one! – when the comfort cooling isn’t operating, to show the huge heat gain that comes through the ceiling and particularly the skylight along the roof ridge. This poses a big challenge for the cooling system at the higher level.

Looking at the view across the desks on the mezzanine for the same period confirms how well the cooling does at keeping employees warm – providing they don’t get too tall.

Is your cooling doing its job? Or do you have a concerns about where your heating ends up? Let us know about your most perplexing HVAC challenge and we’ll help you diagnose what is going on.

Interning at Purr – Doing ‘all of the things’.

<We’ve had some great people come and do internships at Purrmetrix. Say hello to Fiona, our latest colleague, who’s agreed to answer a few some questions about her work experience here.>

Tell us about yourself?Screen Shot 2016-09-06 at 13.28.42

I’m Fiona, a sixth form student in Cambridge currently in the midst of applying to study engineering at university, and, for the last two weeks, a work experience intern at Purrmetrix.

What is all that fiddling with PCBs you’ve been doing?

All of the things!

Screen Shot 2016-09-06 at 11.38.07Over the last two weeks, I’ve got forty-eight gateways ready to go – this involves a small amount of soldering on each one, cleaning the components on the PCB, fitting the antenna, and installing the whole setup into the case. Once this part is complete, I’ve had help to find each individual gateway on the system so that I can get the correct passphrase for it printed out and stuck onto the case, along with the serial number. Finally, each gateway gets plugged in (only using one socket, since these ones have power over ethernet) so that I can check it’s transmitting to the system and install the latest version of our software onto it. Then the gateway is ready to go!

Screen Shot 2016-09-06 at 11.40.00But a gateway by itself isn’t much use…. So I’ve also been involved in building ninety-six kittens. My job covered the first few steps in the process of turning a sheet of circuit boards into a fully-functioning kittens: extracting them from the sheet, plugging them in via the programming widget, and installing the software that enables them to transmit their temperature data to the gateways. Once this update was done, I soldered a radio antenna onto each kitten to improve its range of transmission – and then passed them on to Winston for some more advanced testing and the final stage of assembly.


Was it all engineering?

Screen Shot 2016-09-06 at 11.52.27No! Throughout my time here, I’ve also been involved in other aspects of the company. This means going to meetings, and getting stuck into other types of task. I spent some time doing market research for Hermione – starting with some fairly abstract googling, and ending up with a (colour coded!) spreadsheet of the relevant information.

As well as that I’ve been creating a demonstration account. This needed a major Kitten Hunt around the office to find all of the kittens left in random places during test runs (this went fine until I found some on the ceiling, which were slightly out of my reach). I then took my pile of found kittens and used the system to identify them. Those that were involved in testing were returned to the person in charge of the relevant project, and I “adopted” the rest. I then put the “adopted” kittens into a new project and spent some time creating views for them that will later be used for demonstrations.

This was a great opportunity for me to really get to grips with the data outputs for the kittens, and the full range of analysis that the software can do.

What’s it like?

It’s a really friendly company – everyone here seems to be happy to explain things to me and to teach me how to do whatever I need to know for my latest task. Being set a variety of jobs is great, as it means I get to learn loads of new stuff and see how lots of different aspects of the company work. There’s also a set of company mugs with the kitten face logo on, which I found slightly too exciting…. All in all, I’ve had a great time learning lots of new stuff, building things, and finding out about Purrmetrix during my time here!

<Awww, thanks Fiona. You’ve got great kitten herding skills! Also insane ideas of what makes a good biscuit


Interested in an intern role in Purrmetrix? Get in touch with us – we are always interested in hearing from people who want careers in engineering or marketing. Baking skills not mandatory.>


Installing Kittens In Your Rack – Data Centre


If you have just taken delivery of your first set of kittens ready for deployment in your rack or you are thinking about ordering then I’m hoping to give you all the info you need to get them fitted. It’s not a difficult process and the installation guide will talk you through the basics but there are a few tips that I want to give you to help along the way.

One of our limited edition black kittens in a rack.Optimal kit installation:

  1. Our recommended kit for a rack would be a 8 temperature sensors, 1 temperature and humidity sensor and 1 gateway. This is to give you the best coverage and  the best visibility of your rack on the heat map.
  2. Fixing your kittens – We have found that it’s best to use the cable ties provided for the data centre environment. It’s warm and dry so it’s not the best conditions for sticky pads, they will work but we prefer the reliability of the cable ties. The doors on the front and back of the racks should be easy to slip the cable ties through.
  3. 4 of the kittens should be placed at the front of the rack equally spaced from top to bottom in order to get a full spread of temperatures to see whats going on in the whole rack.
  4. 4 of the kittens should be placed in the same way from top to bottom in the back of the rack.
  5. If you have purchased a humidity monitor then try fixing that in the top of the rack to see whats going on overall.
  6. The gateway is going to need power and an ethernet connection. You will be provided with a normal UK plug socket for the power, if you require power over ethernet then just let us know (extra cost).
  7. The gateway will need to be fitted within the rack for best signal, it can be sat on a shelf, on top of a server or better still attached to the top of the rack with cable ties.


  1. The kittens sense the temperature from their faces so make sure you face the kitten in the direction that you want the most sensitivity.
  2. Rename the kittens when you get them so you can easily know where they live. You can do this by clicking on the kitten and editing the name (you can also add notes to the notes field).
  3. If you aren’t sure which kitten you have in your hand at any one time just push the kittens nose, till the LED lights up (red for the normal temperature sensors and green for the humidity sensors) and it will flash up on your account.
  4. Don’t forget that you can move the kittens about as much as you like. If you have a problem area in a rack you could alway re group them all around a few machines for a few days or weeks to see whats going on. Just don’t forget to change the names of the kittens and change the heat map so you can see exactly whats going on.
  5. Try playing around with different view for your heat map like the rack views from the front or back, different analytics and even hot or cold alerts to get the best out of your purr account.

If you want some ideas about the kind of insights you can get from the information check out our previous blog: Using onboard monitoring? Here’s four things you’re missing.