Tankless Water Heater Venting

Tankless Water Heater Venting

Tankless Water Heater Venting

Tankless water heater venting can be a quick and affordable job if you plan it right.  When many consumers learn that a gas-powered Tankless Water Heaters must be vented, they immediately imagine costly and invasive carpentry work.  However, this doesn’t have to be the case and usually isn’t.  This Tankless water heater guide takes a closer look at tankless water heater venting.

Why Tankless Water Heaters Need to be Vented

Electric tankless water heaters do not need to be vented, but gas tankless heaters do.  The reason is because, like a standard water heater, they create dangerous combustion gases when they fire.  The gases contain carbon monoxide.  However, it doesn’t have to be an expensive hassle to vent. Before you buy your tankless heater make sure you consider which power source is best for you.

Direct Venting Tankless Water Heaters

Tankless water heaters use gas very efficiently to heat water.  And virtually all of the heat, usually over 90% of it, is directly transferred into the water.  Very little of it is lost out the vent.  Because of this, the vent gases are warm but not hot.  Therefore, they can be vented directly out the side of the house rather than having to be vented through the roof. This is just one of the many advantages they have over standard tank-style water heater.

tankless water heater venting
Typical installation of a ventilation for a tankless water heater. This was the installation of a Takagi model. I cannot do the Takagi review because I need to have the unit available and open it completely.

With conventional water heaters, the exhaust gas can be well over 100 degrees F, hot enough to burn or damage plants, siding, etc.  To vent them, a flue must be run up through the roof of the home which can be difficult and expensive.  In addition, any time you put a hole in the roof, even if the protective boot is properly installed, you run the risk of a water leak.  If the boot is damaged by a storm or falling debris, a serious leak and significant damage can be the result.

Since the exhaust of tankless water heaters is relatively cool, it can be vented through the wall instead of the roof.  This is much easier and it is more affordable since it uses far less material and takes much less time to do.  If you have a high-efficiency gas furnace, it will be vented out the side of your home too, so you can take a look at that for comparison.

Installing your Tankless Water Heater for Easier Venting

To make venting easiest, install your tankless water heater on an outside wall.  If the unit is installed on a basement wall, the vent pipe can be run up just a few feet and then vented out the side with the use of a 90-degree elbow.  If the unit is installed on the first floor or above, the vent can be run straight out for the tankless water heater.  All that is needed is a small-diameter hole, PVC vent pipe, and perhaps a housing around it.  The vent should never be covered with a screen, however.  If it were covered with a screen and the screen became clogged, it could cause carbon monoxide to back up into the house.  Cage-type fittings can be placed over the vent to prevent birds from nesting in it – similar to what you see on the roofs of houses that have traditional vents.

Installing a Tankless Water Heater Outdoors

Most manufacturers of gas tankless water heaters make units that can be installed outdoors, even in cold regions.  They use extra energy because they have their own freeze prevention system.  The advantage of outdoor installation is that no venting needs to be done at all.  The wall does need to be penetrated, however, for the cold water supply and the hot water feed into the house.  Outdoor units are often installed in a recessed wall box so that their piping is run in heated space.  Other outdoor units use an electric heating cable that self-regulates to keep water pipe from freezing. The Rheem H95 is a great outdoor unit for most areas of the country.

Summary

Using a tankless water heater offers many advantages, and the ease and affordability of venting it is just one of them. When you choose a gas tankless water heater, you’ll save on energy use over a conventional water heater and on the cost and hassle of installing it

Recommended Articles

We have some articles that I would like to recommend to the readers.

Foundation Repair And Maintenance

We have described here the type of foundations, what is a foundation inspection and what should be included in a good foundation inspection checklist. We can discover problems in the foundation to make us ask ourselves if it is safe to live in a house with foundation problems, and what entails a foundation repair. Not only the repair activity itself but how it affects our wallets.

I explain if the foundation repair is actually covered by homeowners insurance and the actual foundation repair cost. We disaggregated these foundation repair costs and determined, the cost per pier when footings or piers are the solutions for the settlement of a foundation.

To repair a foundation, the service provider might require an underpinning system using piers: push piers vs helical piers where helical piers are preferable for residential real estate objects, despite their costs. Also when you compare helical piers with concrete footings, we can determine that helical piers are more cost-efficient than concrete footings, in my opinion.

We have water in the crawlspace, which can be an issue for the whole foundation if the problem persists, and an additional difficulty when selling a house with water in the crawl space, as it can provide the prospective buyer with a lot of bargaining power, so what can we do: I explain what to do when the crawlspace is flooded or there are simply puddles of water always standing, thus I describe how to remove quickly the water in the crawlspace and how to prevent the problem for the future. So I discuss if it is normal to have water in the crawlspace after a heavy rain, and the importance to perform a crawlspace waterproofing thereafter, normally by installing a vapor barrier.

I describe how to improve the air quality in the crawlspace and to accomplish this, I am reluctant to use lime powder in this article, where I explain the pros and cons, as I would be using lime powder only to avoid the dangers of raw sewage under the house.

We discuss the sill plate replacement cost and how to avoid the outdoor sump pump freezing because it happened to me once.

There are always new methods for repairing foundations. One of them that we investigate here is the Powerbrace foundation repair method.

Animals can be a problem when they live near the foundation: In the following articles, we describe how to remove them and how to prevent them from digging and burrowing. The articles are about animals digging holes around the foundation or when they are burrowing below concrete, below a concrete slab, or between gaps in concrete footings, for example.

In regards to basements, I describe how to solve the hydrostatic pressure in the basement, which is a lateral pressure that is the main cause for having a basement wall that is bowing, or that can be caving in or buckling. While a slight inward curve for basement wall bowing is acceptable, after that degree, you have to address the issue and face sometimes relatively high basement wall repair costs.

I provide to you some reasons why we will need a certified specialist to deal with a risky sewage backup in the basement because bacteria survive a long time in a contaminated sewage network, and also we discuss how to deal with a basement drain backing up in general and what to do when it happens only when flushing the toilet, something that is not a DYI project at all.

Concrete

I explain here the process of concrete lifting or concrete raising, which can be done through mudjacking or slabjacking. We recommend the latter, which injects polyurethane foam.

Framing

There are some interesting articles here, in this Framing category. I refer to sistering floor joists, as a methodology to reinforce existing floor joists with some emphasis on sistering 2x6 floor joists or sistering with 2x8 instead, and about the building code for sistering joists, for sistering rafters, and the code for notching floor joists.

Many of these problems have a consequence: sinking or sagging floors.

Water Heaters

About water heaters, we have a complete guide about water heater types and their installation requirements, about power vent water heaters, and venting in tankless devices, and I also explain in detail the difference between a mobile home water heater and a standard water heater. I also describe in detail how to remove the heating element without an element wrench using just a socket, and how to fix leaks.

We have a few reviews when a water heater falls into our hands, such as the Titan product portfolio, Navien lineup, the Titan N-160 reviews, the most praised by our readers, and the Rinnai R94LSi.

I study several water heater capacities and tested 20-gallon water heater units and a comparison between point of use and tankless water heaters.

We open a tankless water heater to show how does it look like inside a tankless water heater, and how to protect your water heater against the effects of hard water. I also explain the pros and cons of tankless water heaters because many people consider that tankless units are better than standard heaters and it is not always the case.

After the lifecycle of the water heater is over, I reveal to you different options to proceed with its disposal.

Electricals

Just because they became popular and related to current news, I study how to identify aluminum wiring and once discovered, how to proceed with its remediation or retrofit.

Pest Control

I have a featured article where I compare Orkin vs Terminix pest control services.

Photo of author

BY M. Kogan

Hello, I am Marcio. I am an architect and designer, alma mater is Mackenzie. Retired in theory, but an architect never retires completely. Along with architectural projects, I am a filmmaker and have completed some short documentaries. Filmmaking and design are my passions. In HomeQN I write about home decoration and foundations. The goal is to teach homeowners to DYI as much as possible, and when this is not possible, enable them through knowledge, to evaluate service quotations and choose the best service technicians.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.