When buying a hot water cylinder, there are a number of fairly specific things that need to be taken into consideration. These items come in a number of shapes, sizes, functionalities, and prices. You need to know what you’re looking for. The following are some the basic considerations you need to be aware of when getting ready to buy a water cylinder for your home.
You want to get a hot water cylinder that is efficient. This means that it uses fuel in an economical way. Heating hot water in your house can represent a large portion of your heating bills each year, so you want to manage this cost and avoid paying more than you have to.
As with many other products, there are better and worse designed models as well as models that are more efficient for certain uses. There is something that can help you out here as well: many hot water cylinders display what is known as an EF (Energy Factor) rating. This rating tells how efficiently a heater converts energy into heat. It also indicates how much heat is lost while the hot water is being stored. Higher EF numbers are what you want. You want this number to be as close to 1 as possible.
Type of Fuel:
The type of fuel your cylinder will use is another consideration. The main options are gas or electric heaters. The primary advantages to gas heaters are that they are less expensive to operate and continue during power outages. However, they must be vented to the outside of the house, can be slightly more dangerous, and require more money to install initially.
Electric cylinders are quite safe, cheap to install, and tend to work well. However, as noted above they have higher running costs - electricity is fairly expensive. Make a choice between these options based on what your up front and long term budget is and whether you already have gas lines running to your house.
Whole House or Point of Use:
Most hot water cylinders are whole house systems. That is, they supply hot water to all the appliances in the entire house. But some may be considered "point of use" cylinders. That is, they are used with a specific plumbing appliance like a single sink or shower. They may be installed underneath these fixtures and supply hot water only to them. So consider which of these you need, since obviously a point of use cylinder will not need to be as large or energy consuming.
Capacity is the volumetric consideration. There will likely be detailed information on this included with the cylinder itself. Basically you need to suit the size of the cylinder to the number of kitchens and bathroom you have and the appliances they contain. You can determine gallons per minute (gpm) flow rates for each appliance, add them all up, and then see if the cylinder is rated for that capacity.
The dimension of the cylinder is the amount of literal space it takes up. Cylinders will have dimensions printed on them or you can measure them yourself. This mainly is a consideration regarding how much space the cylinder will take up in your basement or wherever you will place it.