7 Best Tankless Water Heaters for Large Homes – Top Picks & Buying Guide 2023

Looking for the best tankless water heater for your large home of 2000, 3000, or even 5000sq ft? I have got you covered, just keep reading. 

The thing with large family homes is the large hot water demand. You may have 2,3 or even 5 bathrooms, and bathtubs that may need hot water all at the same time. This can get pretty difficult to fulfill if a proper size tankless unit is not installed. But don’t worry about this part, I will help you with that. And one of the best locations to install tankless units in such big houses is the central location so you have a minimum hot water waiting period.

With that being said, let’s jump straight to the reviews and discuss which model would be the perfect fit for your household needs. And as an added bonus, I have included a brief buying guide that will help you shop better.

REVIEWS: Best tankless water heater for large home

Rinnai RU199iN is probably the largest residential tankless water heater out there. With upto 11 GPM hot water capacity, the unit is perfect for homes as large as 5000sqft. It can supply unlimited hot water to upto 7 fixtures at the same time. We tested it and found that you can use upto 5 baths or showers all at the same time without experiencing any flow or temperature drop. 

Speaking of construction, the gas-fired model is of condensing style which means it’s a little expensive but is more efficient at upto 0.92 UEF and doesn’t require any expensive venting. You can use cheaper PVC venting too and flue gases are not very hot. 

Another feature is the circ-logic technology which ensures you get hot water faster to your required fixture. But the thing is you will have to buy the GTK03 pump separately. The same goes for the WiFi feature that enables remote access to the water heater. 

Rinnai V94iN is another ideal tankless water heater for large houses. It’s a smaller model compared to the one mentioned above. The 180,000 BTU unit can shell out upto 9.8 GPM of hot water at max in warm climates that can handle upto four showers and a few sinks, all at the same time without flow drop. Or if you live in colder climates like Minnesota then the unit can provide as much as 4 GPM hot water for two showers at a time and in that case, if you have large needs then you will need to install two units in line. 

Besides, V94iN is half the price compared to RU199iN that we discussed above. But it also has a lower efficiency rate of 0.81 UEF and requires expensive steel venting. 

It comes with wifi control as well but you will have to buy it separately. The unit has a scale detection feature that alerts you whenever excess scales build up. Rinnai 9.8 GPM offers a 10-year manufacturer’s warranty on the heat exchanger. 

Noritz EZ98 is an EZ series high-performance tankless water heater made in Japan. The 9.8 GPM unit is identical in most of the features to Rinnai V94iN like wifi capability and Max heating capacity. But yes, this unit work on a pretty low input of just 5000 BTUs which means a lower activation flow rate. 

Unlike most other models in this list, Noritz EZ98 comes with a special grade stainless steel heat exchanger which as per the manufacturer provides an excellent, long-lasting service. In fact, they are providing the longest 25 years of warranty on it. 

This tankless model is available in both natural gas and liquid propane options and you can install this unit either inside or outside of your house. And by the way, it’s a condensing water heater so you are not gonna have any complaints about efficiency. It has a nice 0.97 Uniform Energy Factor and you can use cheaper PVC for venting. Lots of savings.

Although Noritz EZ98 is slightly expensive, you are eligible for a $300 in rebate with this model. 

The prestige series Rheem RTGH-95DVLN-2 is the cheapest condensing tankless water heater in the 9+ GPM size segment. But the cheapest doesn’t mean it compromises on quality. It features a high-durability construction with stainless steel body and copper heat exchanger. 

It registers over 9.5 GPM Max hot water flow in warm climates which is sufficient for a triple bathroom and dual kitchen setup. The maximum hot water temperature is over 140°F.

Rheem Prestige equips hot start technology which promises to greatly reduce the cold water burst. Being a condensing model, the water heater has 0.90+ energy efficiency and is energy star certified. 

If you want to save your precious home space and also want to be stress-free from the baggage of the venting system then an outdoor tankless water heater is best for you and Rheem V75EP is just the tankless water heater you need. 

The outdoor unit requires no sophisticated venting as it releases flue gases from the front side. It is a 7.5 GPM model that is available in both liquid propane and natural gas variants. If you live in warm climates then this size model can support upto 3 bathrooms and a kitchen all at the same time. For houses in a colder region, you might need to install two units as the GPM drops drastically. 

Compared to all the models mentioned above, this model is rather less efficient with a 0.82 uniform energy factor. It has a scale detection feature that gives an alert for excess scale builds. It also equips a temperature lock feature that prevents accidental temperature changes and thus helps avoid scalding. You can find more affordable non-condensing tankless water heaters like this here.

If you have a shortage or supply problem of natural gas or propane in your neighborhood then a single or multiple-unit setup of electric tankless water heater is best for large homes. Especially households in warm regions are ideal for electric counterparts.

The German Stiebel Eltron is a 36kW high-power tankless water heater that can shell out more than 7 GPM hot water. It’s also more energy-efficient at 99%. The model is energy star certified. 

Let me introduce you to the construction of this unit. The Stiebel Eltron 36kW equips a triple copper heat exchanger that has high heating efficiency and bundles 7 years of leakage warranty. It has the dimensions of a small suitcase that can fit anywhere inside your home. And there’s a temperature control knob and display for convenient use. 

The last in our list of best tankless water heaters for large homes is another electric model. This 27kW unit from Ecosmart is ideal for the southern US. If you have a house with 2 or 2 and a half bathrooms then this model is perfect for you. With 99% of energy efficiency, this heater can render upto 6 GPM of hot water. 

The water heater has a triple heat exchanger set up and is operated via self-modulation that saves water and energy whilst providing you with consistently hot water. 

The only thing is the customer service which I have experienced to be a little less dependable. 

BUYING GUIDE: What to look for when shopping for a tankless water heater for a large home

There are a few things that you need to look for when you are out shopping for a tankless water heater for your big 2000sqft, 3000sqft, or even 5000sqft homes with upto 5 bathrooms. We will talk in brief about those down below.

Size of tankless water heater

It is the single most important factor when choosing a tankless unit for your home. Choose the wrong size and face a frustrating situation of lack of hot water down the road.

Size here means how much hot water a tankless water heater can provide per minute which is measured in GPM ( or gallon per minute). First, calculate how much hot water you can use during your peak hour. Say you have 5 bathrooms and all 5 showers are used during the morning then, 

5 (shower) x 2 (shower flow rate) = 10 GPM

You will need a water heater that supplies at least 10 GPM water flow in this case.

Temperature rise

Temperature rise, in simple words, is the difference between the temperature of your desired hot water and cold water temperature in your home. 

Say you live in Florida where the average cold water temperature is 72 degrees F, and you want hot water to be 105 degrees F which is normal hot water then,

105F-72F = 33 degree F

The temperature rise you need in this case is 33 degrees F.

Remember while selecting a tankless water heater, temperature rise and size are considered together. This is because, with higher temperature rise, hot water flow drops. So make sure when selecting a tankless water heater the flow rate match the rise you want. And don’t sweat, all manufacturers provide flow rate tables that you can refer to.

Indoor /outdoor style

Regardless of having a large, big house, people prefer installing one unit inside while another outside. The manufacturer gives clear guidelines as to where the unit should be installed. So you can’t install an indoor unit outside or it will get damaged.

The best thing with outdoor units is that you don’t need to build an expensive venting system but the bad thing is the risk of theft.

Fuel: Natural Gas/ Propane/ Electric

I will advise you to go with the one that’s easily available and cheaper in your locality. If you have a blackout problem in your city then you definitely won’t wanna go with an electric model. If gas is cheaper then you should go with that. Especially people living in cold regions should go with a gas-fired tankless water heater. More on the tankless water heater for the cold region here.

Frequently asked questions