The following is a guideline for sizing hot water heaters for residenical use, that was developed from years of experience and from other sources.
| How many people are living in the house? | 1 2 3 4 5 6 7 8 9 10 |
| How many baths or showers are taken daily? | 1 2 3 4 5 6 7 8 9 10 |
| How many Dishwashers do you have? | 1 2 3 4 5 6 7 8 9 10 |
| How many Washing Machines do you have? | 1 2 3 4 5 6 7 8 9 10 |
| Do you have a whirlpool bathtub? | Give each tub the valve of 2 |
| Total |
| If your total from about is 4 or less | 30 gallon Lochinvar Hot Water Heater |
| If your total is 5 - 7 | 40 gallon Lochinvar Hot Water Heater |
| If your total is 8 or more | 50 gallon Lochinvar Hot Water Heater |
| If your total is 8 or more and you have a whirlpool bathtub | 65 or 75 gallon Lochinvar Hot Water Heater |
Please note that your results may vary depending on which brand and model of hot water heater you choose. As with any major purchase you should consult you local hot water heater expert. And remember quality is never cheap, its just good!