Fred derf fred: I too was set on going tankless - till i saw the upcharge. It is coming to about $5,750 more to go with (4) gas tankless (Rinnai 94LS 9.4gpm top of the line) compared to State gas water heaters - as spec'd in the drawings of our house. I did research and found out that gas tankless do have an EF (efficiency rating) of .82, however GAS (i believe you compared electric tank) tank heaters commonly have .62, and a few have .68 efficiency. This results in savings of tankless is about $250 per year, for all 4 units combined. So it would take me more than 20 years to recoup the cost difference. This was based on a formula as provided by the dept. of energy. Additionally, State, who sells both, has a 'calculator' on their website that corraborated the results. Also, please note that your existing ELECTRIC tank heater was very OLD. New, gas models are much more efficient so I do not think it is a fair comparison. I am no expert, but these are my findings. I would greatly appreciate any other comments ASAP as we are about to make the decision on going tank or tankless

Rick, Thanks for your reply, and please forgive my VERY tardy response. I've been pondering what you've said, and reading here at the Plumbing forum, and to be honest, I'm feeling overwhelmed. Here's where the overwhelmed part kicks in. We've done small, homeowner-type DIY plumbing jobs before: stuff like moving the kitchen drain line, adding a dishwasher and disposer, adding an ice maker, and changing out faucets; we're pretty skilled with PVC (built and designed a pond, with pump and drains); we've added, moved, and removed vent pipes, but I think I've hit the point in my research where I know enough to be dangerous, and I know enough to know how much I DON'T know. Hence the feeling of rising panic. Our fair city isn't DIY friendly but we could never afford to do any renovations if we had to bring in trades to do it all, so we've always worked without permit but been hyperviligent about over-engineering things and never violating code, in fact, we always shoot for our work to be as good or better than the best trade work available. We've cleaned up a lot of very scary previous home owner DIY messes. It looks like no pex is yet allowed here (too DIY friendly?), so we're back the copper. Pex home run systems seemed easy to understand and build so they were properly balanced, but I'm having a hard time wrapping my head around the proper sizing and placement of a copper trunk and branch system for the same fixtures. Right now, the system we inherited has mix of iron and copper supply that feeds: the boiler supply, laundry hook ups, and 2 hose bibs on the basement level 1 full bath (toilet, sink, and tub), plus 1 kitchen sink (plus DW and icemaker) on the 1st floor 1 full bath (toilet, sink, and tub) on the 2nd floor. What we want is this: boiler supply plus 2 hose bibs plus 1 full bath (toilet, sink, tub/shower combo) plus laundry hook ups and laundry sink, plus wet bar in the basement 1 half bath (toilet, sink) plus 2 kitchen sinks (1 now, adding 2nd sink later) on 1st floor 1 full bath (toilet, sink, tub, separate shower) plus laundry hookups on the 2nd floor. Can I feed all that with my 3/4" main supply? In truth, the only really demanding fixtures are the 2 tubs (one standard tub/shower combo, one clawfoot) and the new 2nd floor shower (which I'd like to plumb with a shower panel or at least a shower head, handspray, plus a few body sprays and a steam generator, but I'll downgrade that to a normal showehead if I can't run that much water). My washer is an Asko, and while we plan to plumb both H & C to both laundry locations, the washer only needs a cold supply, and only uses about 8-9 gallons at a time. It's not impossible we'd want to use both showers at once, but we've never had that capability before. The rest is all toilets and sinks. We can live with no showers while running a hose bib, heck we can't use anything while there's a hose bib open now and the hose just trickles!) One of the things we realized was going to hang us up with a true home run system using Pex (before we found out it's not code here yet) was that we simply didn't have anyplace we could run that many pipes across the finished basement (the joists run the wrong way and there's only 1 small chase we can use). The main supply line runs in the front of the house, and all the bathrooms and kitchen are in the back half, but the chimney is in the front, so that's where we need to locate the new gas water heater we'd like to add. We need to move the existing electric water heater, which sits two thirds of the way back in the house under the wet wall for the 2 current bathrooms, because that's where we need to put the tub for the basement level bath, and we want to upgrade to gas before that 30+ yr old water heater gives up. Don't worry, we aren't doing the gas/vent for the water heater ourselves, we have a friend who is a contractor who will help us out with that part. If I have a 3/4" main, that means I need to feed the water heater with 3/4" in, and reduce to 1/2" coming out, right? Also, I need to reduce the cold side of the T before the water heater to 1/2" for the cold supply? My DH wants to run 1 set of 3/4" trunks for both H & C all the way to the back of the house and then reduce to 1/2" branches. I think he's wrong and that will lead to a lot of balance problems with the hot and cold. I'm also not sure that's enough water to supply all the fixtures. If necessary, I guess we could upgrade the main supply, but it would have to be after we finished and cleaned up any current construction so we didn't get dinged for being handy around the house. I'm sure I'll have a couple of questions about the DWV side of the equation too, but at the moment, I'm pretty sure we can solve any issues there with little worry. It's the supply side that is keeping me up at night. I feel bad even asking these questions, because I feel like y'all will tell me to just hire a plumber, and it's not that I don't respect all the training and knowledge that a real plumber has, I simply can't afford to bring in a pro to do this large a job. I also don't want to screw this up! Thanks for any replies and please be gentle! Always ;-) Hunzi

fxdbdennis makes some good points; However, if money is limited, two tankless units would be expensive. I think the important thing is to understand what the goal is. For some people, unlimited hot water is the priority and they are willing to pay for expensive tankless unit(s)to get it. Some even add a recirculating pump that makes the hot water to the faucet almost instantaneous at the cost of significant standby losses. Other people are interested in energy savings (even if it doesn't make financial sense). Still others want a system that is economical over the life of the system -- be that tank or tankless. What I understand from windyhill_gardener is that they are looking for a way to not vent through the chimney-- something that can be accomplished with a powervent tank unit or a tankless unit. I also hear that they want to lower their utility bill, again something they could do with either type of unit-- with a small advantage to the tankless unit. I also got the sense that budget is somewhat of an issue since they have not replaced their old 80% or less furnace yet and that this is an older home where running a new gas supply is not likely. I am also guessing that they don't have major hot water uses (jacuzzi tub) since they have an existing 40 gal tank. If my assumptions are correct, my advice would be to go with the 50 gal powervent unit and put any additional money towards the furnace. This would provide a significant quantity of reliable hot water at a good efficiency while keeping installation costs reasonable and allowing for the elimination of the chimney. It's hard to justify spending an additional $1,000 -$1500 for a single tankless unit in order to save $50 a year on the gas bill when the furnace needs to be replaced. With all of that said, I want to be clear that I am not negative on tankless units. For some applications they are a good choice.

Surely, there is a way to shut off your water. You need to shut off the water to change washer hoses, work on sinks and toilets, etc. Locate your water meter. There should be two shutoff valves, one in the feedline to the meter and another in the water line leaving the meter that supplies the house. These two valves are needed to change out the meter. In my town, meters are changed out every 10 years for calibration and/or updates. In my state, there is a 3rd shutoff not accessible to the homeowner and it does require a special tool. This valve is buried at the lot line where your supply line connects to the city or association supply. Its at the lot line were city/utility employees may turn off the water without entering your property and do not have to get a court order. About your washer hoses. Trace your washer hose from the back of the washer to its source. Normally, these hoses (hot and cold water) are connected to a faucet or valve and may be behind the washer. A nice installation places these valves above the washer so they can be reached without moving the washer.