With the increase in energy prices all over the World, hot tub users are looking at ways in which they can economise the cost of using and heating their tubs. An Air Source Heat Pump is a great way of doing this.
Like anything, choosing the size of your ASHP is very subjective. However, I like to make things easy so here is my quick guide. Firstly, you want to go for the largest Air Source Heat Pump that fits into your budget.
In my opinion, there is no point in adding a 5KW ASHP to your existing Hot Tub. Whilst some may disagree, I don’t believe that the gains are worth the expense. As a bare minimum, again, in my opinion, you should be looking at a 9KW or above for a 4-6 person tub. Any tub larger that this, you should be looking for 12KW as a minimum.
Air Source Heat Pumps go up to very large sizes so what is the upper limit I should be thinking about? Again, this is a subjective matter, but in my opinion, you don’t need any more than a 24KW Air Source Heat Pump on your hot tub.
The bigger the pump, the quicker it will heat up. Also, the bigger the pump, the less the heat up time will be affected in cooler weather when the output drops. This is the reason that I don’t believe a 5KW heat pump is useful as in the cooler months, your output might be dropping down to 2 or 3KW.
Select your Location for your Air Source Heat Pump
The first thing you need to do is decide on a location for the air source heat pump. You need to choose a location where there is good air flow. You need to have space all around the air source hear pump, ideally 30cm / 12” from a wall.
You need to make sure that there is nothing in front of the fan. For example, you cant have the Air Source Heat Pump boxed in or inside of a shed. They don’t work like that. You should always check the manufacturer’s installation guidelines but as a general rule, you must have good air flow right around the unit and they most not be covered or restricted in any way.
How much pipe do you need?
Next, you need to measure how much pipe you are going to need to get to and from your hot tub. Remember, the water needs to flow into the air source heat pump, be heated, then flow back into the hot tub. Measure the distance to and from the hot tub to your proposed location for your Air Source heat pump, then add 30% extra. This is how much pipe you need.
It is also a good idea to think about insulating the pipes if they are above ground. In this way you can minimise the heat loss as the water travels to and from the tub.
What size pipe do I need?
In general, on Hot Tubs, water lines or pipes are 2”. Therefore, I would recommend that the water lines are 2” to and from the air source heat pump. This is to make sure that there is enough flow available.
Post time: Jun-29-2022