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TimJFowler · 07-31-14, 02:48 PM

Hello all,

I am searching for a replacement for our 40 gallon tank Natural Gas water heater. The current water heater was a cheap replacement ~12 years ago (~.50 energy factor) so almost anything will be an efficiency improvement. I've done some research [e.g. http://www.greenbuildingadvisor.com/...-water-heaters ] and given our particular constraints and requirements I've narrowed the choices down to two general categories:
A) Conventional Natural Gas Tank Water Heater
B) Solar Thermal Tank w/ backup heat source.

Here is my thinking, requirements, issues:

1. The water heater is located in a utility closet in the central hallway and the replacement needs to go in the same location. I'm not interested in re-plumbing the house to move the water heater, and there isn't room for a much larger water heater.

2. We are a family of three and don't use a lot of hot water (for 32 days in June/July we used 5.7 therms of nat. gas for cooking and hot water combined). So a tankless water heater doesn't make much sense for our use.

3. A heatpump water heater "creates cold" which could be useful in summer, but during the winter would create a cold spot in the center of the house.

4. A condensing gas water heater is relatively expensive (compared to a conventional gas burner) and would need a drain plumbed in.

5. We have cold winters where temperatures regularly go below freezing overnight. So, any solar option should be freeze-proof.

6. We live in a sunny locale but a backup heat source would provide peace of mind for us.

7. Any more expensive option should have a realistic payback period (i.e. within the warranty period).

So that leaves me with
A) an efficient, conventional nat. gas tank water heater for ~$580 plus installation:
- ex. Rheem Performance Platinum Series: Powered Damper Series - Rheem model # XG40T12DM40UO
OR
B) Solar Thermal w/ nat. gas backup for ~$4500 plus installation:
- ex. Rheem SolPak with Gas Assist Heat Exchange Tank Series - Rheem model# RSG75-48BP

I'm looking for suggestions, alternatives and any other info that I've missed. Are there less expensive, but reliable / warranteed solar thermal options that meet my requirements?

Thanks,
Tim

07-31-14, 02:48 PM	#1
TimJFowler Apprentice EcoRenovator Join Date: Dec 2008 Location: Santa Fe, NM Posts: 184 Thanks: 9 Thanked 12 Times in 11 Posts	Nat. Gas vs. Solar Thermal Water Heater Hello all, I am searching for a replacement for our 40 gallon tank Natural Gas water heater. The current water heater was a cheap replacement ~12 years ago (~.50 energy factor) so almost anything will be an efficiency improvement. I've done some research [e.g. http://www.greenbuildingadvisor.com/...-water-heaters ] and given our particular constraints and requirements I've narrowed the choices down to two general categories: A) Conventional Natural Gas Tank Water Heater B) Solar Thermal Tank w/ backup heat source. Here is my thinking, requirements, issues: 1. The water heater is located in a utility closet in the central hallway and the replacement needs to go in the same location. I'm not interested in re-plumbing the house to move the water heater, and there isn't room for a much larger water heater. 2. We are a family of three and don't use a lot of hot water (for 32 days in June/July we used 5.7 therms of nat. gas for cooking and hot water combined). So a tankless water heater doesn't make much sense for our use. 3. A heatpump water heater "creates cold" which could be useful in summer, but during the winter would create a cold spot in the center of the house. 4. A condensing gas water heater is relatively expensive (compared to a conventional gas burner) and would need a drain plumbed in. 5. We have cold winters where temperatures regularly go below freezing overnight. So, any solar option should be freeze-proof. 6. We live in a sunny locale but a backup heat source would provide peace of mind for us. 7. Any more expensive option should have a realistic payback period (i.e. within the warranty period). So that leaves me with A) an efficient, conventional nat. gas tank water heater for ~$580 plus installation: - ex. Rheem Performance Platinum Series: Powered Damper Series - Rheem model # XG40T12DM40UO OR B) Solar Thermal w/ nat. gas backup for ~$4500 plus installation: - ex. Rheem SolPak with Gas Assist Heat Exchange Tank Series - Rheem model# RSG75-48BP I'm looking for suggestions, alternatives and any other info that I've missed. Are there less expensive, but reliable / warranteed solar thermal options that meet my requirements? Thanks, Tim __________________ - DIY Adventures in Applied Sustainability - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by TimJFowler; 07-31-14 at 04:17 PM.. Reason: add model #'s