How do I know which size of storage tank I need?

There are many answers to this question but it really boils down to this…you need the one that best suits your application, your solar collector field, your budget and your available space.

If you use a Heliomaxx kits from Sunmaxx, we have sized the storage vessels relative to the size of the collector field. For sizing, we generally consider first the temperature requirement of the tank. For instance, if you need your solar tank to be a cetain temperature before it ties into your home heating sytem then we would likely reduce the storage capacity but if you are using your tank as a pre-heat system only then we try and maximize the storage. And also we need to consider your budget, because even though a bigger tank give us more solar gain annually, there may not be the payback on that larger tank that justifies the expense. Here are the ratios we typically use for storage relative to solar collector area:

1 gallon per Ft2- high temp loads or in northern climates with flat plates

1.5 gallon per ft2- medium temp loads and typical with most Flat plate installs

2 gallons per Ft2- high temp loads for Evacuated tubes or Low temp for flat plates

2.5 gallons per Ft2- medium temp loads for EVT

3 gallons per ft2- low temp loads

4+ gallons per ft2- sometimes it does make sense but would need to be analyzed based on payback.