water heater source for 4000 sq. foot house?
rockybird
12 years ago
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Billl
12 years agoionized_gw
12 years agoRelated Discussions
Help me choose a hot water heater, recirc pum, tankless or vertex
Comments (0)We are in the process of building a house. Currently our plan includes a 75 gallon tank located in the garage. We have a 2 story home, about 4000 sq ft. 2 baths(1 is guest, used infrequently), kitchen, laundry down. 3 baths, stackable laundry center up. We are concerned about getting hot water to the other side of the house where the master bath is located. We have 4 very young children, under 8 yrs old. So not alot of simultaneous morning showers now, but that could come in a few years. Here are our options: 75 gallon w/recirc pump = $1800 two 50 gallons w/recirc pump = $1800 + $575 Tankless Rinnai (adequate for 2 showers running same time)= $1408, if we need 2 smaller system add $1442 50 Gallon Vertex On Demand = $1771 The Vertex seems to be a good option if it can provide us with enough hot water? Please give me you opinions/experience!...See MoreWhat type of water heater are you putting in your new home?
Comments (23)ncamy the gas fired tankless units I have looked at (and the ones I have - Rinnai's) will not work unless they have electricity to operate the digital controllers and the electric igniter. But the amount of electricity required is very small - probably less than a few amps. I put the outlets that my Rinnai's plug into, as well as my well pump, on my backup generator so that when power is out, i have both hot & cold water. If you do decide to go with tankless - only consider gas units. The electric whole house tankless units require a lot of current - far in excess of what your typical household backup generator can supply. On the flip side, tanked systems are much easier to implement a recirculating system. With a tank - all you need is a small pump and the return loop line. With a tankless system, you have to add a small holding tank on the output side of the tankless - and that holding tank will most likey be a small electric tank (mine is a 4 gallon tank). If you don't put that holding tank in, then your tankless units will fire whenever the loop pump is running (could be for hours) since they use water flow to detect when to turn on. And if that happens, you will hate your gas bill. You can also look at a hybrid system. As an example: if your second floor suite is mostly for occasional guests - use tankless for that suite so that you don't have to continuously cook water with a tank. You could then use a tank for the master suite. You could also look at point of use hot water tanks which could service a kitchen or bathroom sink. Point of use units require an electrical outlet (most require a dedicated circuit) to be installed below the sink. As long as you plan for it ahead of time - this isn't an issue. But adding these outlets after the house is done can be a challenge.. There are many possibilities for the hot water power plant - all of them have strengths and weaknesses. But none of them can overcome a poor plumbing design. You have to look at your house design and determine the best way to plumb it for the hot water - always keeping in mind that the longer the length of the main feeder lines to the source, the longer the delay for the hot water. It is also very hard to get a perfect system because of the way houses are typically layed out and constraints for running the pipes. Unfortunately, the hot water plumbing design is generally an afterthought. During our build, we did think about placement of the tankless under the master suite but never realized that this selection would cause such long delays in the kitchen which is over 100 feet away. Thankfully we were able to fix this issue witha recirculating system but it isn't an optimal solution. Hopefully you can avoid these pitfalls....See MoreHelp me pick the water heater type for my radiant heat system
Comments (3)"Also have mixing valves at each zone with out door reset. So you can control the temp of the water by the outside temp." This. The boiler needs to be sized for the design limits, and the rest of the time (actually almost all the time) is oversized. Using a boiler wit an indirect tank and a reset thermostat allows the tank to serve as the buffer between system size for the coldest hours and the actual needs of the house when temperatures are milder. The boiler heats the tank and runs hot enough to not be damaged. The temperature in the tank is controlled by a reset thermostat based on the outdoor temperature. The zone valve allow final tempering for each zone based on their actual requirements....See MoreDoes Tankless Hot Water Heater = Inconsistent Hot Water?
Comments (36)riellebee So I'm going to rough-in some numbers: Range: 15k btu/h Fireplace: 80k btu/h Furnace: 75k btu/h (x2) = 150kbtu/h water heater 200k btu/h (x2) = 400k btu/h Total potential load: 645k btu/h - again, an estimate. You can check your furnaces if you want to be be sure. is it likely that you would have enough things on at the same time to exceed your 425k btu/h service? - Yes, it's quite likely. What happens when you exceed the capacity of the service? The gas pressure drops and the range and the gas logs will just not run at full capacity - no big deal. But the things like the furnace and water heaters will throw error codes showing low gas pressure. The water heaters are likely to have that problem anyway, because at 30' of 3/4" pipe they are only getting about enough gas to run one of those heaters full tilt (the water heaters are variable input). The meter may be 20' away, but in actual length of pipe it's probably close to 30' including elbows. I can see close to 10' of pipe in the photo. The fact that the return line for the circulation isn't warm suggests it's not working. Fix that and insulate your pipes and your immediate problem will probably go away. BTW: Insulating the pipes is not expensive or difficult. Foam pipe insulation comes in 4' sections that just snaps around the pipes and uses self adhesive strips to hold it closed. It cuts with scissors. Even if you just did the exposed pipes in the basement you would reduce a lot of heat loss. My guess is that the builder can't really fix the "over-subscribed" gas service at a reasonable cost. One solution is to use a different water heater. A hybrid tank/tankless would solve the problem. The link goes to an AO Smith Vertex 75 gal water heater 100k btu/h and is 92% efficient and vents with the PVC vent pipe you have. I'm not particularly endorsing that brand - just using it as an example. It would provide you with plenty of hot water (you could run 1 shower continuously) and would reduce your BTU load by 300k BTU/h (gas service problem AND undersized gas pipe to water heater solved). In addition, because it's a tank of hot water - along with about 6' of hot water in the pipe - your wait would be significantly reduced even without a circulation pump. It sucks for your builder because it would cost them about $3500-4000 to fix it. They could probably realize some salvage value from the tankless heaters - say $1000-1500. But If they are only out $2-3k total I'd say they should consider themselves lucky....See MoreBilll
12 years agoweedmeister
12 years agorockybird
12 years agobeth4
12 years agoweedmeister
12 years agorockybird
12 years agoionized_gw
12 years agorockybird
12 years agobeth4
12 years agorockybird
12 years agoionized_gw
12 years agoweedmeister
12 years ago
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rockybirdOriginal Author