There's a lot of back-end technology to improve and automate demand response programs, but one of the most powerful tools is already in consumers' hands: the smartphone.

Honeywell on Tuesday announced that by early 2014, all of its Wi-Fi thermostats will work with utility-sponsored demand response programs. Right now, only one of Honeywell's Wi-Fi thermostats can integrate with demand response for two-way communications. There will also be a firmware upgrade for existing products.

A key part of the offering is the associated app, called Total Connect Comfort Services, which lets users control the thermostat settings via a smartphone or tablet. Using that app, consumers can enroll in demand response programs and respond to notifications from the utility.

Wi-Fi thermostat makers are quick to tout how much easier those products are compared to conventional programmable thermostats. But the vast majority of utilities are finding that communicating with consumers about demand response events through texts and email is the most effective route, said Jeremy Eaton, vice president and general manager of smart grid solutions at Honeywell.

"It's where homeowners are naturally spending their time, so we're just piggybacking on technology and behavior of homeowners that's happening anyway," said Eaton.

Honeywell believes there is a shift toward operating demand response through Wi-Fi thermostats rather than direct HVAC controls. That could help increase enrollment and participation in those programs to reduce power use at peak times on hot summer days. 

"The real trick is to convince the homeowner to participate. It's much more compelling to offer a Wi-Fi thermostat with a top-rated iTunes app, which is something they want anyway to control their [thermostat] remotely," said Eaton. Opting out of demand response, for example, through a thermostat setting change on a smartphone is a lot quicker and easier than having to call a toll-free number.

Unlike direct controllers, Wi-Fi thermostats can communicate back to utilities as well. For example, they can report on how many air conditioners in an area are available at a given time and forecast what the level of power shedding could be. Honeywell’s partnership with Opower to offer energy-efficiency recommendations complements the demand response feature, said Eaton.

Honeywell now has more than 600,000 one-way thermostats and 2 million control devices tied to demand response programs at more than 100 utilities in North America. Earlier this year, the company released its first thermostat that is compliant with automated demand response, a product that is being used by the municipal utility in South Sioux City, Nebraska.

Starting next year, all of Honeywell’s Wi-Fi thermostats will have that same two-way communications capability and the ability to tie into Honeywell’s Open Automated Demand Response (OpenADR) program, which it acquired from Akuacom.

With competition heating up in smart thermostats, Honeywell is under some pressure to upgrade its product line. There’s competitor Nest, which earlier this year announced utility partnerships to offer demand response through its app and thermostat. And then there are broadband service providers. Comcast earlier this year introduced a service that combines cloud-based analytics with a smart thermostat.

The thermostat war continues -- and it is going mobile.