Professur
Well-Known Member
The time it takes to fill the 5 gal pail will tell you your gal/m ratio. That's critical to ensure that the heater can heat the water fast enough at full flow. Higher amp units can heat either the same amount of water per minute to a higher temp, or a larger volume to the same temp. An example (pulling the numbers outta my ass)
a 20A unit can heat : +35C@ 5g/m .. +30C@6g/m .. +25C@7g/m
a 30A unit can heat : +40C@ 5g/m .. +35C@6g/m .. +30C@7g/m
So knowing the temp you want to achieve and the flow rate lets you see (on the manufacturers chart) which unit will best serve.
These heaters do have one significant advantage over a hot water tank, which is also it's prime disadvantage .... sized correctly, you never run yourself out of water. This can lead to much longer showers than planned, and an inordinately high hydro bill as a result. Also, their short time draws are significantly higher. Cost savings are only realized when the water in your tank sits stagnant for a time. The more hot water you use in a day, the less your savings will be. Much like a hybrid car, you only really save gas in heavy traffic. In fact, the difference can be even more greatly balanced by upgrading to a modern hot water tank, and wrapping a hot-water tank jacket around it and insulating any hot water pipes you can access.
BTW, if you don't have anyone else and want/need help replacing the tank, I've done several. Alternately, my tooling is at your disposal. No point in buying all the kit when mine sits idle.
a 20A unit can heat : +35C@ 5g/m .. +30C@6g/m .. +25C@7g/m
a 30A unit can heat : +40C@ 5g/m .. +35C@6g/m .. +30C@7g/m
So knowing the temp you want to achieve and the flow rate lets you see (on the manufacturers chart) which unit will best serve.
These heaters do have one significant advantage over a hot water tank, which is also it's prime disadvantage .... sized correctly, you never run yourself out of water. This can lead to much longer showers than planned, and an inordinately high hydro bill as a result. Also, their short time draws are significantly higher. Cost savings are only realized when the water in your tank sits stagnant for a time. The more hot water you use in a day, the less your savings will be. Much like a hybrid car, you only really save gas in heavy traffic. In fact, the difference can be even more greatly balanced by upgrading to a modern hot water tank, and wrapping a hot-water tank jacket around it and insulating any hot water pipes you can access.
BTW, if you don't have anyone else and want/need help replacing the tank, I've done several. Alternately, my tooling is at your disposal. No point in buying all the kit when mine sits idle.