October 19, 2017
Where you’re not getting hot water out of the system if it’s working properly but what we do have is a certain amount of hot water that’s available per minute or flow that’s available from the tankless water heater and let’s face it you have a burner system that can only heat the water so fast right so a typical home when a home inspector needs to look for to size to make sure that the water the tankless water heater is sized properly was how many fixtures are in the house and what what is the maximum flow that that household could be using at any given moment and what we typically like to do is match that flow up to that demand if we can you can’t always do that and sometimes owners a buyers need to understand that they may not be able to turn everything in that house on and get flow out of all those fixtures so can an inspector test that by turning on a representative number of fixtures that hot water fixtures at one time and timing.
How long it takes to run absolutely and what’s going to happen with most tankless water heaters is that when that flow rate that maximum flow rate that’s available because of the size of unit we have is exceeded the flow will drop in all of those fixtures so for example we have two showers going which typically is the maximum flow available from a tankless water heater here in Colorado at the altitude where we are as well as the cold incoming water temperature that we have here in Colorado or water because coming in at 40 degrees in the winter time and 50 degrees in the summer so that’s another thing an inspector can measure what is our incoming water temperature if he wants to it’s real simple to get you know a laser thermometer yeah maybe that’s something I’m sure that they carry with him they should should measure the the incoming water temperature typically we want to see in Colorado an 80 degree rise or other parts of the country where you don’t size for an 80 degree rise Southern Florida for example the water is coming in at 75 degrees the water’s coming in 75 degrees we don’t to get it to 120 is only a 40 degree rise or 45 degree rise Dave what does an inspector need to know in order to determine whether or not the tankless water heater is sized correctly for the home well typically we do have some flow rates .
That oftentimes are posted on the side of the unit again if we don’t have a manual we can look at the flow rates for the particular unit that’s there and take a look at the different how many fixtures there are in the house and how each one would affect the flow coming from this unit so for example the typical hand sink is 1.2 to 1.6 gallons per minute of flow the typical shower is 1.8 to 2.2 gallons per minute of flow and what we’re talking about here is flow from 40 degree incoming water to 120 degree that’s what we need to look at for for colder climates for warmer climates that’s different but you just look at what temperature the incoming water is typically a dishwasher is 0.9 to 1.1 gallons per minute where we run into issues are bathtubs Jacuzzi tubs and old-style washing machines because all of these things do dump a tremendous amount of water at once if you’ve ever watched a jacuzzi tub and with the Roman faucet on it there’s six to seven gallons per minute of water that that thing’s dumping that’s way more than anyone tankless water heater any one tankless water heater can handle before that flow is dropped.
So you know typically if an inspector goes into a home that has a jacuzzi tub and there’s only one unit and he measures the flow at that jacuzzi tub at six or seven gallons a minute what you can do with a stopwatch in a bucket very simple gallons per minute then he needs to know that that that this unit is not going to be able to handle that plus anything else in the house without a reduction in flow right and again it’s about education it’s about the the person who’s buying that house understanding what it is they’re getting and that they’re gonna have to adjust their lifestyle to a tankless water here and when you say reduction in flow that actually means reduction in flow not that the water will get cooler like a desk with a conventional water heater that’s correct with a conventional water heater runs out of hot water it’s done and until it comes back it’s cold water it’s no longer hot water tankless water here the more modern the newer units what will happen is that flow will drop yes on the older units if they’re running into some of the older aqua stars some of the older Palomas some of the older Takagi’s the thing that they’re gonna see is that they don’t adjust the flow there’s no capacity of the unit to actually adjust the flow of water through what this flow Raider does it actually adjusts the flow of water so it comes out slower to keep that same output temperatures that you have set on the controller the older units are much less sophisticated than that they don’t have a computer they have no way to do that so they’re gonna drop the temperature and people are gonna get cold showers and the old units.
Yeah Daveour inspector is likely to see electric tankless water heaters and what about point of useful are heaters there are electric tankless water heaters manufactured the problem that we see with them is that they require tremendous amount of electricity obviously if anyone’s ever cooked on a gas stove versus an electric stove the difference in time that it takes to heat water on a gas stove is considerably less isn’t it so typically heating water with gas instantaneously like this a continuous flow takes a lot less energy to do so what we see with electric tankless water heaters is they could consume up to 140 amps of power at 220 volts and most homes don’t have that capability so we don’t really see a lot of them out there no and as far as a point of use units the only point of use units that are available in the United States our electric units so we’re kind of back to that same problem what we really see for point of use are very low flow ones that can make a cup of tea for example you got 120 degree or 130 degree water coming out but it’s a tiny amount of 120 degree water so you might usually see those in a kitchen just serving the kitchen sink and maybe the dish was exactly.
I mean you go to Europe and Asia and places across the puddle and you do see gas point-of-use water heaters but they are illegal here there’s no way to put them in what about the cost advantages in installing a tankless water heater well a tank type water heater of course is considerably less than a tankless water heater but one of the things that has come to the forefront recently as the new naica standard the national appliance an energy conservation act has mandated for tank type water heaters a new standard and that actually has thinned the laws of the heat transfer tube and at the same time the jacket of the new tank water heaters so when you go out to buy a new tank water heater today the typical life expectancy is three to five years of a new tank type water heater and that’s by government mandate and that’s just because of thermal cycling heating and cooling and stressing the the over time well as we know the tank type water heater it’s usually a glass lined rolled steel tank and what happens over time yes is that through contraction and expansion that glass eventually cracks well now we’re relying on that metal to keep that water in now if the metal is one-third the thickness that it used to be it’s gonna take a lot less time for that tank type water heater to explode and go all over the place so why did they do that the government issued a mandate as I said the naica standard.
It was was brought about by Reagan in 1978 if you see the yellow guides like this mm-hmm Energy Guide see that on every appliance that’s naked a tional appliance energy conservation act that was started back in 78 and applied to furnaces and air conditioners refrigerators every home appliance has that yellow energy guide on it well in 2004 they realized that they needed to do something with water tanks because they are the most inefficient appliance in any home bar none less efficient than even an old furnace so they reduced the what the license so they reduced the lifespan because their thinking was if we can thin the wall of the heat transfer tube that goes all the way up through the middle of the tank we’re gonna get more heat into that water quicker aren’t we so that is correct but what did they increase the efficiency by any guesses one and a half percent one and a half percent so the new water tanks save all of 10 bucks a year over the old water tanks.