Endless hot water only works if the gas line, the vent and the water are set up right. I check all three before I quote.
You've got a full house for the weekend and the tank runs dry after the second shower. Or the old tank is 12 years old and you're done with it. Either way you're thinking about going tankless. I'm Sergio, and I do tankless water heater installation in Malibu, CA, from simple swaps to full conversions from a tank.
A tankless unit heats water only when you turn on a tap. No big tank sitting there keeping 50 gallons hot all day. It's a great setup when it's sized right. When it isn't, you get cold-water surprises and error codes. So I start with the boring stuff: your gas line, your vent path, and your water.
Sound familiar? These are the calls we get most.
The tank empties before everyone's showered, and then you wait around for it to heat back up.
Rust on the bottom, a damp floor, or a tank past 10 years. Good time to think about tankless.
Often a gas line too small for the burner, or a scaled-up heat exchanger from hard water.
Flame failure, venting or flow codes. Most point to gas, vent or mineral buildup issues.
You want the floor back. A wall-hung unit frees up the spot where the tank used to sit.
New house, new plumbing. Good chance to plan the gas line and vent for tankless from day one.
Homes & vacation rentals
Most of my tankless jobs are homes swapping out an old tank, or rebuilds where we can plan the gas and venting from scratch. I keep the work area clean and I explain how to run the unit before I leave.
Request Residential QuoteShops, restaurants & property managers
Restaurants, salons and vacation rentals burn through hot water fast. I size the unit, or a pair of units, for your real peak use, not a guess.
Request Commercial QuoteSame four steps on every tankless water heater installation job.
Count showers, tubs, sinks and appliances that can run at once, then size the unit to that.
Measure pipe size and length from the meter. A big tankless burner often needs a bigger gas line.
Pick the shortest safe vent route, with the right vent material for the unit you choose.
Mount it, add service valves for descaling, test gas pressure, fire it up and show you the controls.
Here's the part a lot of installers skip. A typical tank heater burns about 40,000 BTU (a unit for how much gas it uses each hour). According to Rheem's gas piping guide, a whole-house tankless unit can run from 140,000 up to around 200,000 BTU. That same guide says a unit near 200,000 BTU generally needs at least a 3/4 inch gas line, and sometimes 1 inch, depending on how long the run is.
A lot of older homes have a 1/2 inch line feeding the tank. Hook a big tankless to that and the unit starves for gas when the stove and furnace are running, and you get a cold shot halfway through your shower. Rheem also notes a typical home gas meter is rated around 250 cubic feet per hour, so I add up every gas appliance you have. If the line or meter is too small for a tankless water heater installation in Malibu, CA, I tell you before you buy anything. Sometimes it means a new gas run, sometimes a call to the gas company about the meter.
Honestly, not always. Tankless is great if you have a big family, guests a lot, or want the garage space back. The Home Depot cost guide quotes the U.S. Department of Energy: homes that use 41 gallons or less of hot water a day can get 24% to 34% better energy efficiency from a tankless unit than from a tank. Rheem says tankless units can last 15 to 20 years or more, compared to 8 to 12 for a tank.
But the upfront cost is higher, and the unit needs yearly care in hard water. If you live alone and use little hot water, a good tank may be the better deal. Before any tankless water heater installation in Malibu, CA, I'll tell you which way I'd go and why.
Tankless units are sized by flow, in gallons per minute (GPM). ENERGY STAR lists typical flows: about 2.5 GPM for a shower or tub, 2.2 for a sink, 3.3 for a clothes washer and 1.3 for a dishwasher. Two showers and a sink running at once is about 7 GPM.
Incoming water temperature matters too. Colder water means the unit has to work harder to get it hot. For tankless water heater installation in Malibu, CA, I size for your busiest morning, not your average one. For bigger houses or rentals, two units linked together can make more sense than one giant one.
Venting. Tankless units push out exhaust, so the vent has to be right. A. O. Smith explains that condensing units (the high-efficiency kind) vent with PVC pipe, while non-condensing units need stainless steel vent. Condensing units also drip acidic water, so I run a drain line for that. Vent length and where it exits your wall are set by the maker's manual, and I follow it to the inch.
Hard water. Malibu's water from District 29 is hard. The 2024 water quality report shows average hardness of 272 parts per million from one plant and 148 from the other. Minerals build up inside the heat exchanger (the coil the water runs through) and choke it. Rinnai says to flush the unit at least once a year, using about 4 gallons of plain white vinegar pumped through it for up to 45 minutes.
So every tankless water heater installation in Malibu, CA I do gets service valves on the hot and cold lines. That makes the yearly flush a quick job instead of a cut-the-pipe job. I can do the flush for you, or show you how and you can do it yourself.
A straight tankless swap can be done in a day. A tank-to-tankless conversion with a new gas run and vent can take longer and I'll tell you the plan up front.
For cost, here are national ranges. The Home Depot lists tankless installs at $2,400 to $5,400, about $4,300 on average. Malibu homes with long gas runs or tricky vent routes tend to sit higher in the range. You get my price before any work starts.
Time: a tankless swap usually takes one day. A conversion from a tank with new gas line and venting can take longer.
Mess: drop cloths, careful wall work for the vent, and I take the old tank with me.
Permits: in Malibu, permits go through City of Malibu Building Safety. In Pacific Palisades, LADBS requires a plumbing permit for most gas water heater replacements. I pull the permit and meet the inspector.
Cost: national range for tankless water heater installation is $2,400 to $5,400 per The Home Depot. For tankless water heater installation in Malibu, CA, you get one upfront price with the gas and vent work included.
Last updated October 2026.
Straight answers to what people ask on the phone.
All plumbing FAQsYes, if you take care of it. District 29 water is hard, and minerals build up inside the heat exchanger. Rinnai says to flush a tankless unit at least once a year with white vinegar. I install service valves so that flush is quick. Some homes also add a softener or scale filter ahead of the unit.
Often, yes. A tank burns about 40,000 BTU, while a whole-house tankless unit can run up to around 200,000. Rheem's gas piping guide says a unit that size generally needs at least a 3/4 inch line, sometimes 1 inch. I measure your line and add up all your gas appliances before I quote.
Rheem says 15 to 20 years or more with proper care, compared to 8 to 12 years for a tank. The big thing that shortens its life here is scale from hard water. A yearly flush keeps the heat exchanger clean and keeps the unit running like it should.
Nationally, The Home Depot lists tankless installs at $2,400 to $5,400, about $4,300 on average. Your price depends on gas line size, vent route, and if you're switching over from a tank. I look at all of it first and give you one upfront price before any work starts.
Many models come in outdoor versions that mount on an exterior wall, which saves indoor space and skips the long vent run. Near the beach, salt air is hard on metal, so I look at where the unit will sit and whether it needs a cover or a better spot out of the spray.
Text or call (310) 359-0140. I'll check your gas line and vent first, then give you one upfront price.
