What Size Tankless Water Heater Do I Need? A Mad Pipers Plumbing Guide
If you’ve ever stood in a cold shower wondering, “What size tankless water heater do I need?” you’re not alone! At Mad Pipers Plumbing, we help homeowners figure out the tankless water heater sizing puzzle every day. Getting the right size isn’t just about comfort—it’s about efficiency, saving money, and making sure your family always has enough hot water.
Why It’s Important to Get the Sizing Right for Your Tankless Water Heater
A tankless water heater is different from those big storage tank water heaters you might remember from Grandma’s house. Instead of heating and storing gallons of water all day, a tankless heating system gives you hot water on demand. But, the magic only happens if your tankless water heater size matches your home’s peak demand and flow rate needs. If it doesn’t, you could end up with lukewarm showers—or worse, no hot water at all when you need it most!
Let’s walk you through tankless water heater sizing step by step—Mad Pipers style.
Step 1: Calculate Your Home’s Peak Hot Water Demand
To size a tankless water heater, the first thing you need to know is how much hot water your home uses when everyone needs it at once. This is called your home’s peak demand. Think about those busy mornings when someone’s in the shower while the dishwasher is running and the washing machine is working hard in the laundry room.
The GPM Magic Number
Tankless water heaters are sized by something called GPM (gallons per minute). This tells us how much hot water, by volume, you need at your busiest times. Here are a few examples of how much hot water commonly used household appliances need:
- Shower: 2 GPM
- Kitchen faucet: 1.5 GPM
- Bathroom sink: 1 GPM
- Washing machine: 2 GPM
- Dishwasher: 1.5 GPM
Example: Let’s say during your family’s morning rush, you have:
- 1 person in the shower (2 GPM)
- One kitchen faucet running (1.5 GPM)
- Laundry running in the wash (2 GPM)
Total hot water demand: 2 + 1.5 + 2 = 5.5 GPM
That means you’ll need a tankless water heater with a flow rate of at least 5.5 GPM to keep everyone happy—no cold-water surprises!
Step 2: Know Your Incoming Water Temperature
Another key to tankless water heater sizing is knowing your incoming water temperature. That’s the temperature of the water coming into your home from outside, which can be super cold in the winter and a little warmer in the summer.
The required temperature rise is the difference between your incoming cold water temperature and the temperature you want for your hot water (typically around 120°F). The colder your incoming water, the harder your tankless water heater has to work.
- If you live somewhere cold (like in the Twin Cities!), your tankless water heater might need to be a little bigger, since it has to heat icy water fast.
- In warmer places, you may be able to select a smaller size.
Wondering about your home’s incoming water temperature? Don’t worry—Mad Pipers Plumbing can help you figure this out during a water heater installation or consultation.
Step 3: Check the Specs—Selecting the Right Tankless Water Heater
Now that you know your GPM and required temperature rise, you’re ready to choose a correctly sized tankless water heater. Each model lists its maximum GPM at different temperature rises, so you want to pick a unit that matches your home’s needs—even during peak demand.
Pro Tip:
Look for a tankless water heater that can handle your highest water demand—and don’t forget to factor in your coldest incoming water temperature!
Need Help Sizing or Installing a Tankless Water Heater? Call Mad Pipers Plumbing!
Choosing the right tankless water heater size doesn’t have to feel like rocket science. At Mad Pipers Plumbing, our friendly experts will:
- Accurately calculate your maximum hot water flow rates and peak demand
- Assess your incoming water temperature and plumbing layout
- Recommend the perfect sized tankless water heater for your family
- Provide fast, safe, and professional installation
- Offer repairs, routine maintenance, and 24/7 emergency plumbing services
We only install models we’d trust in our own homes, so you know you’re getting the best value!
Contact Us Today!
Unsure about what size tankless water heater you really need, or ready to make the switch to energy-efficient, on-demand hot water? Call Mad Pipers Plumbing anytime or email us at [email protected]. Visit our website at madpipers-plumbing.com for more info or to schedule your tankless water heater consultation.
In Summary: Get the Perfect Tankless Water Heater for Your Home
What size tankless water heater do I need? It depends on your peak hot water demand (GPM), your flow rate needs, and your incoming water temperature. With the right size, your family will never run out of hot water—plus, you’ll save money and energy compared to traditional water heaters.
Whether you need tankless water heater sizing, installation, or plumbing repair, Mad Pipers Plumbing is your trusted local expert. We help you every step of the way—so you can enjoy long, hot showers every day.
Ready to get started? Contact Mad Pipers Plumbing today and experience hassle-free, expert plumbing service!
