How Much Does a Heated Seed Mat Cost to Run?

This is a question I hadn't thought too hard about in years gone by, but as we are all well aware, things have changed recently. And with the price of electricity skyrocketing, some of the electrical goods we used to run without thinking about can now come with a substantial cost attached.

With this in mind, I decided to find out exactly how much my heated seed mat costs to run. So I got a cheap power meter and tested the seed mat.

Above is a link to the heated seed mats I use if you want to buy one. They are just a cheap generic Chinese brand, but I have had them for around four years now, and they still work well, so no complaints from me.

What The Manufacturer Says

The manufacturer says the mat draws 17.5W, and we can use that to work out what the cost per day should be. So if we run the mat for 24 hours a day, which is what I do, then the usage is 0.42kWh per day.

Then we take the now standard electricity rate of £0.34 per kWh, and we get a cost per day of £0.14.

In 2021 the average price per kWh of electricity was £0.17, so the same seed mat would have cost £0.07 per day.

So even though the price has doubled, it will only cost the same as a packet of seeds to run per month.

But this is if what the manufacturer is telling us is correct. And we all know what kind of "facts" Chinese manufacturers often print on the box.

So I plugged it into the monitor and let it sit for a while to get a proper reading.

So I got the monitor set up and set the price per kWh at 34p. The current standard rate for electricity.

What The Testing Says

So what results did I get from the power meter? Well, straight off the bat, it is recording a higher usage than 17.5W, often coming in at 19W or above.

Above, you can see it running at 19.7W. The average was about 19.5W so let's use that for our calculations.

At 19.5W, the price increases from £0.14 to £0.16 per day, so not a massive increase but still a little higher than what the manufacturer would have you believe.

Just to make sure the readings were accurate, I also ran the mat through a second power meter, which gave similar results. This one gives you the data on an app.

So there we have it. If you get a similar heated seed mat to mine, then you are looking at a running cost of around £0.16 per day if you have the seed mat running 24 hours a day at current energy prices (Jan 2023). I hope this information helps you out!