In the middle of November, I bought and installed a NestThere were no problems whatsoever. But then, a twist. The thermostat started to go nuts. The temperature would race over 70 degrees, even though I had the thermostat set for 60 or The Nest's problems became most pronounced on Christmas Day. wife and I were away visiting family on Christmas eve and during were heading home, we turned on the Nest to have the house got home, the house was more than pre-heated. It was like a The temperature was ~72 degrees when we got in. I turned down the thermostat, but the heat kept on cranking. As we sat in the house, the temperature climbed to 76, even though I turned the temperature to 55 on the thermostat. We went to sleep, but the heat was still cranking. So I got up and turned off my boiler altogether. In the morning we turned it back on, and the Nest seemed okay. But that later that night, it lost its mind again and cranked the

heat in the house. Two days later, I called Nest to find out what was wrong with theI spent 1 hour, 50 minutes talking to customerLuckily, it was two days after Christmas, so it was a slow news day, and I was working from home. to be on the phone for two hours. Normally, this isn't an option. The Nest customer support person was really friendly, and quite helpful, despite the long talk time. Eventually, he decided I had a "power sharing"Basically, the Nest powers itself with the wires in the wall. Those same wires send a signal to the boiler to turn on the heat. Every time it was trying to give itself a charge, it sent a signal to the boiler to heat theAs a result the heat kept cranking and cranking even though it was just the thermostat trying to get juice. I'm not the only one that has had this problem, either. Amazon's reviews of the Nest warn of this happening to other person had the same problem. did this person, who explains the problem, "The method

they use to get power is a huge problem. require a C wire so they can power themselves. The issue is, many homes don't have an extra wire to use for this purpose. attempt to remain DIY friendly, they implemented a technology referred to in our industry as 'power stealing' which tries toair conditioning units mounted on wall get power from the HVAC control wires and is notorious for manyac unit running in reverseMight as well just be straightforward about it andac unit emergency heat require a C wire in the first place. There are kits such as Venstar's 'add a wire' which make it easier to solve the problem without having to pull wire." As one reviewer noted, this is The house can crank up to dangerous

temperatures when you're not at home, and the consequences could This is 100% on Nest. hooked up my thermostat, it gave no indication that there wasAnd the fact that it worked for a few weeks was even worse since I was lulled into thinking everything was To fix the problem, Nest recommended I find a local technician from its website. offered a $99 credit towards any fixes since I am a new customer. I was told that my $99 credit was not guaranteed, but I would be likely to get it. It took four days for a technician to get out to my house. In those intervening days, I had to yank the Nest off the wall when I didn't want the heat When the technician came to the house, he fixed the problem relatively easily, but charged $135. So, if the credit comes through, I'll be paying an extra $36 for the Nest on top of the $250 I paid for the actual I don't mind too much because I really like the product. still recommend it to people.

But, the fact that Nest knows its wiring system is faulty and doesn't warn people that'll they need a third wire is a big At no point did I say that I am a writer for BusinessWhen I decided to write this up, I reached out to Nest PR to give it a heads up. A spokesperson provided the following statement: "We see this with a small percentage of customers and typically handle it the way that your case was handled, by covering the cost to have one installed. (I understand that we requested your receipt and planned to cover the entire cost, notWhile we find that in the vast majority of homes the Nest Learning Thermostat can charge its built-in battery using the heating and cooling wires, there are a small number of heating and cooling systems and situations where the Nest Thermostat may require a common wire to bring power to the about to raise $150 million at a $2 billionA big part of the funding is based on the idea that it makes a product that

It oohs and ahhs people with its gorgeous design, andBut if it's causing problems for even adept users like myself, this could be a big problem in the long run for theMod #37: Digital Thermostat Mod Rating: (187 ratings) The standard analog thermostat found in most RVs doesn’t control the A/C and furnace with much accuracy. The “set” temperature is not always the temperature the thermostat cycles, which results in as much as a +/- 5°F temperature change before the A/C or furnace cycles on or off. This is known as the hysteresis of the thermostat. For example, if you have the furnace set at 72°F, this could mean the temperature would fall to 67°F before cycling on and rise to 77°F before cycling off! These temperature swings aren’t very comfortable so what to do? The digital thermostat mod of course. Analog thermostats have what’s called a mechanical heat anticipator, which essentially tells the thermostat when to cycle. Some anticipators are more accurate than others but for the most part are not very good at controlling temperatures accurately.

The digital thermostat is much better at temperature control since it controls its hysteresis using electronics to within +/- 1°F degree of accuracy. This mod is commonly performed using the Hunter brand residential thermostat. It’s cheap and very straightforward to install. Other residential thermostats can be used but this one seems to be the most popular. Just be sure the thermostat you select is battery powered. Some residential thermostats use 24 VAC to power them. But if they have the battery backup feature, they can be used for RV 12-volt systems. The wiring diagram above assumes you have a Dometic A/C unit and an Atwood furnace. Other combinations such as a Coleman Mach A/C unit and a Suburban furnace are very similar so be sure to consult your A/C and furnace manuals to ensure correct wiring. See the resources below for some really nice write-ups by fellow RVers who have performed installations with various A/C-furnace combinations. ModMyRV recommends these parts for this mod: