Leaks
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A room-by-room guide to finding hidden leaks in a finished basement: what to check in the utility room, bathroom, laundry area and under the stairs this fall.
Water Heaters
Tank or tankless: choosing a water heater for a Colorado home
Most water heaters get replaced in a hurry. A tank that has been getting by for years finally gives out on a cold November morning, the house needs hot water that day, and the easiest choice is whatever matches the old one. Sometimes that's the right call. But if your tank is getting older, the time to weigh tank against tankless is now, while you still have hot water and can think it through.
Here's how the two compare, followed by which way we'd lean depending on the house.
Tank and tankless side by side
| Question | Tank | Tankless |
|---|---|---|
| How it heats | Keeps a set amount of water hot in an insulated tank around the clock | Heats water as it passes through, only while a tap is open |
| Hot water supply | Plenty until the stored water runs low, then a wait while it recovers | Doesn't run out, but can only deliver so many gallons per minute at once |
| Several fixtures at once | Fine until the stored hot water is used up | Depends on unit size; an undersized unit can't keep up when too many fixtures are open |
| Energy use | Loses some heat standing by, even when nobody is using water | No tank to keep warm, so it typically uses less energy; the U.S. Department of Energy publishes estimates of the savings |
| Replacing an existing tank | Usually a direct swap using the existing gas, venting and water connections | Often needs a larger gas line and new venting, plus a power outlet |
| Space | Takes up floor space in a utility room, closet or basement | Mounts on a wall and frees up floor space |
| Power outage | A gas tank with a standing pilot usually keeps heating; power-vented models don't | Needs electricity for its controls and fan, so no hot water while the power is out |
| Routine maintenance | Periodic flushing to clear sediment | Periodic descaling of the heat exchanger and cleaning the inlet screen, per the manufacturer's manual |
| Expected service life | Shorter | Generally longer, according to the U.S. Department of Energy |
Neither column wins outright. A tank is simpler and usually easier to drop in. A tankless unit gives you continuous hot water and floor space back, but only if it's sized and installed for the house it's going into.
Why tankless sizing is different along the Front Range
A tankless heater is sized by two things: how much hot water the house uses at its busiest moment, and how many degrees the unit has to raise the water to get there. Several local conditions push that math in the wrong direction.
Cold incoming water in winter
The water coming into your house is colder in January than in July. The colder it arrives, the harder a tankless unit has to work, and the fewer gallons per minute it can deliver at shower temperature. A unit that handles two showers in September may only manage one comfortably in midwinter. Size for the coldest month, not the average.
Altitude
The south metro sits at or above a mile in elevation. Thinner air means a gas burner can't produce its full sea-level output, so a tankless heater rated for a certain capacity at sea level delivers less here. Manufacturers publish high-altitude information in their installation manuals, and some models need setting changes or specific parts above certain elevations. That needs to be factored in before choosing a model, not after.
Gas line size
A tankless burner draws far more gas at full fire than a tank burner does. The gas line feeding your current tank was sized for that tank, along with your furnace, range and anything else on the system. If the line can't supply enough gas to the new unit, it won't reach its rated output, and you'll feel it as lukewarm water when the house is busiest. The pipe size, the length of the run and the other gas appliances all affect whether the existing line works or needs to be upsized.
SafetyGas line changes, venting and anything inside a water heater's burner or electrical compartment are jobs for a licensed professional. Don't open or modify gas piping yourself.
Which way to lean
A tank probably fits if this sounds like your house
- Your current tank just failed and you need hot water as soon as possible. A like-for-like replacement is usually the fastest route.
- Your gas line and venting are already set up for a tank and you'd rather not change them.
- You want hot water during a power outage and are replacing a gas tank that has a standing pilot.
- You may move in a few years and don't want to take on the extra conversion work.
Tankless is worth a serious look if this sounds like your house
- Your household regularly runs out of hot water and a bigger tank won't fit where the old one sits.
- You'd like the floor space back in a utility room or basement.
- You're finishing a basement or remodeling, and gas and venting work is already on the table.
- You plan to stay long enough for a longer service life to matter.
- Your hot water use is spread through the day rather than everyone showering at once.
Cases that need a closer look either way
A large household with several showers running at the same time can work fine with tankless, but sizing has to be done carefully, and some homes are better served by two units. Homes with hard water will need to stay on top of descaling a tankless unit. And whole-house electric tankless heaters need a lot of electrical capacity, so the panel and service have to be checked before that's a realistic option.
Decide before the tank decides for you
If your tank is past the expected life listed by its manufacturer, or you're seeing rusty hot water or moisture around the base, start the conversation now. If it's only acting up, water heater repair may keep it running through winter while you weigh the options without pressure.
We install both tank and tankless water heaters across Castle Pines, Castle Rock, Parker, Lone Tree, Highlands Ranch, Centennial and south Denver. Estimates are free, and we'll look at your gas line, venting and space, tell you whether tankless is practical for your house, and quote the job up front before any work starts. Call 720-916-7720 or book online. If the old tank does give out on a cold night, we answer the phone 24/7.
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