MrStop
Member
I had been considering a condensing powered direct-vent (sealed combustion) tank water heater, but I am wondering if I should go tankless instead? I know the tank versus tankless has been beaten to death. However, does the equation change when the tank unit is substantially more expensive and newer/less proven then the tankless unit (assuming similar installation costs)?
BACKGROUND
As posted on the tank forum, I need to replace an older a slowly leaking water heater. We will be remodeling our home soon which involves tightening up the envelope. Because my water heater is located in the basement, my priority is to remove the combustion intake and exhaust air from the equation for safety and so I don’t need to bring in makeup air. Additionally, I would like to eliminate the flue chase (HVAC is already high efficiency). If I can improve energy efficiency, even better!
I was about to pull the trigger on a HTP Phoenix Light Duty 50 gallon water. It has great FHR, recovery and efficiency specs, it looks like it can be easily vented, and the stainless design should provide a longer service life. My concerns are that, like the Rheem RHE50 and AO Smith Vertex condensing water heaters, the service life is somewhat unproven and there seems to very little real world experience with them (at least in the long term). As the tanked units are considerably more expensive ($2000 for the HTP and $1,500-$1,600 for the others), I’m thinking a tankless unit (<$1,300) seems to be a better gamble (longer history, cheaper to replace if it dies). Additionally, I like the idea of the tankless unit taking smaller space.
I am aware of the idiosyncrasies of tankless water heaters (length of waiting time, cold slugs, dropping pressure, etc). I’m prepared to address this via a buffer tank and recirculating system. However, this adds system complexity and starts to negate some of the tankless benefits.
SITUATION
My house is 2 ½ bathrooms. It is occupied by two adults and two children (14 & 11). We typically shower, but the kids will sometimes take a bath (smaller/standard tub). We have low flow shower heads (2 GPM), a HE washing machine, and newer EnergyStar dishwasher. Plumbing runs are currently under about 20’ and we get near instant water today. I will likely convert to a home run system during our remodel.
Our water is served by the city with sufficient pressure. I have learned that I have hard-ish water (11 gpg) and I will be installing a water softener regardless of type of WH. Water supply into the home is ¾”. I’m in Southwestern Ohio, so I assume my cold month water temp could get down to 40-degrees or more, but I haven’t measured.
The current gas line is 1 ¼”. It runs ~41 feet and has 2-90* elbows where it terminates to supply a furnace (80K BTU), a Gas Grill (38K BTU), Fireplace (30K BTU), and the water heater. If I add in a tankless water heater (199K BTU), my total BTU load is ~347K BTU. Based on the charts, my supply line should handle 364-400K BTU. The meter shows a tag with a rating for 250/195 CFM. The regulator is marked as model B-31.
QUESTIONS
1. Should I go with a condensing tank style water heater, OR, a condensing tankless water heater? My assessment summary:
3. If I do go tankless, I think a 199K BTU would be best given my climate. Any preference or experience with the Rheem Series 95? Any concerns over the Richmond equivalent? The Richmond is in stock locally and on sale for about $200 less.
BACKGROUND
As posted on the tank forum, I need to replace an older a slowly leaking water heater. We will be remodeling our home soon which involves tightening up the envelope. Because my water heater is located in the basement, my priority is to remove the combustion intake and exhaust air from the equation for safety and so I don’t need to bring in makeup air. Additionally, I would like to eliminate the flue chase (HVAC is already high efficiency). If I can improve energy efficiency, even better!
I was about to pull the trigger on a HTP Phoenix Light Duty 50 gallon water. It has great FHR, recovery and efficiency specs, it looks like it can be easily vented, and the stainless design should provide a longer service life. My concerns are that, like the Rheem RHE50 and AO Smith Vertex condensing water heaters, the service life is somewhat unproven and there seems to very little real world experience with them (at least in the long term). As the tanked units are considerably more expensive ($2000 for the HTP and $1,500-$1,600 for the others), I’m thinking a tankless unit (<$1,300) seems to be a better gamble (longer history, cheaper to replace if it dies). Additionally, I like the idea of the tankless unit taking smaller space.
I am aware of the idiosyncrasies of tankless water heaters (length of waiting time, cold slugs, dropping pressure, etc). I’m prepared to address this via a buffer tank and recirculating system. However, this adds system complexity and starts to negate some of the tankless benefits.
SITUATION
My house is 2 ½ bathrooms. It is occupied by two adults and two children (14 & 11). We typically shower, but the kids will sometimes take a bath (smaller/standard tub). We have low flow shower heads (2 GPM), a HE washing machine, and newer EnergyStar dishwasher. Plumbing runs are currently under about 20’ and we get near instant water today. I will likely convert to a home run system during our remodel.
Our water is served by the city with sufficient pressure. I have learned that I have hard-ish water (11 gpg) and I will be installing a water softener regardless of type of WH. Water supply into the home is ¾”. I’m in Southwestern Ohio, so I assume my cold month water temp could get down to 40-degrees or more, but I haven’t measured.
The current gas line is 1 ¼”. It runs ~41 feet and has 2-90* elbows where it terminates to supply a furnace (80K BTU), a Gas Grill (38K BTU), Fireplace (30K BTU), and the water heater. If I add in a tankless water heater (199K BTU), my total BTU load is ~347K BTU. Based on the charts, my supply line should handle 364-400K BTU. The meter shows a tag with a rating for 250/195 CFM. The regulator is marked as model B-31.
QUESTIONS
1. Should I go with a condensing tank style water heater, OR, a condensing tankless water heater? My assessment summary:
- Condensing Tank
- Pro's: Cold weather performance; More seamless operation without added equipment
- Con's: More expensive unit; Less “proven”; Unknown life / reliability; Larger footprint
- Condensing TankLESS
- Pro's: Less expensive unit; More “proven”; Potentially longer life; Smaller footprint
- Con's: Cold weather performance; Additional equipment to handle cold slugs / pressure drops
3. If I do go tankless, I think a 199K BTU would be best given my climate. Any preference or experience with the Rheem Series 95? Any concerns over the Richmond equivalent? The Richmond is in stock locally and on sale for about $200 less.
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