There are various things to consider when buying a hot tub (sometimes called a spa). If you have decided to buy a hot tub, you'll be making a considerable investment, either for fun, relaxation and health benefits, or possibly a combination of all three. A decent hot tub is expensive, as you will probably already know if you have seriously considered buying one.
Location - where are you going to put your new hot tub? Location is extremely important. In the United Kingdom especially, most households have a rear garden but in most cases it is not entirely private. Can your neighbours see into your garden? Most people would usually rather use their hot tub in private, therefore you need to consider where is best to locate it within the space you have.
Open or Enclosed - There are pros and cons for each situation. A ready made shelter or enclosure can probably be bought from your hot tub supplier, but it's almost guaranteed to be very expensive- in some cases as expensive as the hot tub itself. You could consider making a simple two or three sided shelter with a roof. If you are unable to do this yourself you could employ a carpenter or tradesman to do it for you.
Some people like to gaze at the stars whilst in their hot tub. An open tub can be fantastic especially when its snowing, or when its freezing cold outside and you are soaking away in your hot tub. Give the open or enclosed option some serious thought as hot tubs are heavy bulky items which aren't that easy to move!
Cost of Running- some hot tubs can be relatively inexpensive to run, but it is likely that your energy bill will rise considerably. Try and be prepared for this so that you're not too shocked the first time you get your energy bill. Most reputable hot tub companies have information available on running costs. Once you establish your regular hot tub usage, you should be able to see how much your hot tub is costing you each week or month.
Warranty - It is likely that your hot tub will develop at least a couple of problems within its lifetime. If the worst happens and things go wrong in the early days (and it does happen), make sure you have bought from a company that stands by its warranty and will offer you the support and back-up you need. The key here is your research. Read everything you can on the subject. Visit every hot tub forum you can to gain an understanding of what might go wrong, what the most common problems are, and which are the best companies for dealing with any problems that arise. People are always sharing their good and bad experiences online so there is plenty of information to digest on the subject. Read enough and you will quickly recognise who stands by their warranties and which companies are likely to cause you problems.
Maintenance - Most modern hot tubs require limited looking after. However it is likely that you will need to add chemicals on a daily basis (sometimes just a capful). Are you there everyday to do it? Are you away from home much, and if so, is there somebody who could do it for you?
Standing & Power Supply - Most hot tubs will require a decent hard standing base of some kind. Check with your supplier company what exactly is needed. Many suppliers will be willing to visit to your home to assess what will be needed. Also check the power supply, in most cases a simple electrical socket won't be good enough.
These are just some of the factors that you need to consider when buying a hot tub. Enjoy your hot tub!