Monday, September 15, 2014

Pipe Heaters

Prevent Frozen Waterfalls on Those Cold Winter Nights with a Wrap-On Pipe Heating Cable

Houstonians, where I grew up folks pretty much rejoiced if a January overnight low only dropped to 20° Fahrenheit, so your "nasty cold snaps" seem laughably warm to me. I kid you not, in seven years I've never worn my second-warmest coat here, much less my warmest - and the best gloves are still somewhere in storage, too. However, I realize that not only are the human beings around here unable to endure sub-freezing temperature, local houses haven't been designed for such temperatures either. So we are prepared: for example, we bought some of those 99¢ foam covers for our outdoor faucets and picked up some foam pipe wraps.

The Problem: Exposed Pipes

One inexplicable local plumbing practice - don't me why, given Houston has a hard freeze every few years - is to pipe to near the edge of the slab with PVC, then finish bringing water to the house through an exposed copper supply pipe. Yep, naked metal pipe outside the house; a veritable full-employment plan for local plumbers if there ever was one. I've outsmarted them, though, because I own a Wrap-On Pipe Heating Cable I'd bought several years ago for our Great (formerly) White Elephant on the Edge of the Prairie. No problems: even after several nights of low-twenties temperatures, we'll be fine -- though our plants probably won't.

The Solution: Pipe Heating Cables

Pipe-heating cables like this employ simple electrical resistance to generate a little heat within a flexible rubber or vinyl strip.  The rubber strip, about 1" wide and 1/4" thick, is intended to be wrapped around rigid "plastic" or metal pipes, then covered with a layer of non-flammable insulating material. According to the manufacturer, when it's been properly installed a cable prevents freezing in the pipes at temperatures down to -50°F. Obviously, I haven't checked the lower limit in Houston. Wrap-On sells their wares in color-coded lengths from 3 to 100 feet. All cables are rated for above-ground use only. According to the documentation, a cable draws two watts per foot of length. All cables have built-in thermostats that activate when the ambient temperature falls to 38°F. Each also has a tiny lamp that glows when there's the cable is drawing power. They all run off standard household current.

Installation Instructions

The packaging provides quite detailed instructions about how to install one of these cables: a strip won't be effective at low temperatures unless it's over-wrapped with insulation, and it must also be wrapped around the pipe according to the instructions. After we spent a waterless week in a high mountain A-Frame whose water supply was "protected" by cables that hadn't been overwrapped, I'm here to say that these are only slightly better than nothing if they're not installed right. With Houston temperatures only dropping to around 20° for a few hours, full insulation in our case isn't as important.

Choosing the Correct Length

Getting the right length is critical: heat cables can't be cut, or plugged end-to-end. A chart on the packaging will help you select a length, depending on the length of the pipe run, the pipe's  OD, and the spacing with which you plan to wrap the pipe (minimum of 2 and maximum of 12 inches). Do your homework before you buy.

I've been completely satisfied with the performance of our cable. Though such a product looks expensive, it's far cheaper than burst pipes. Pipe heating cables are a smart way to prevent a frozen pipe in your attic, crawl spaces garage, or other unheated spaces.


PLUS: near-foolproof way to prevent burst pipes on the coldest night of the year
MINUS: a little expensive, requires planning to get the right length
WHAT THEY'RE SAYING: These may seem expensive, but have you priced a visit from the plumber lately?

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