Solar water heaters, energy and ways to save money and energy remain a hot topic with consumers in these expensive times.

Several readers took issue with the Hawaiian Electric Co. example we quoted last month of potential savings offered by a typical household converting to a solar water heater.

One tax preparer said the example in question doesn't subtract the state credit first.

"I've always understood that the federal credit must be calculated after taking into account the state credit," he wrote.

"I like the credit you illustrated and of course the taxpayer would be the beneficiary of an additional $446 reduction in their tax burden," he wrote.

Another man wrote: "For anyone who itemizes, the federal tax savings will be reduced by the marginal tax on $1,488, the state tax credit, because his/her state income tax deduction will be reduced by the state tax credit.

"This is likely to be a very common situation, as many homeowners have deductible expenses such as property tax and mortgage interest that makes it very likely that they'll itemize."

He said readers who might go solar based on this optimistic scenario could end up spending close to $400 more.

Hawaiian Electric Co. spokesman Darren Pai said the example the company uses — which we printed — is accurate although he emphasized that as an example, it carries a big disclaimer saying it "should NOT be considered tax advice."

Pai stressed that each system is different and consumers should consult their tax adviser, IRS or state tax office. "We're not trying to give people exact advice on how to calculate their tax credits," he said.

But he did cite the July 20, 2006, state Tax Department announcement that the amended state tax credit in Act 240 eliminated the requirement that the federal tax credit be subtracted first. (On the Web, http://hawaii.gov/tax/announce/ann06-11.pdf)

On a related topic, sharp-eyed retired engineer Alan Lloyd questioned another number in that same solar column.

In it, HECO estimated savings of $5 to $10 per person in a household per month when folks convert to a solar water heater.

Lloyd thought that figure was outdated and should be closer to $15 to $20.

Pai checked and said the old number was outdated but said HECO now estimates the conversion would save $10 to $15 a person each month.

"Each household is going to be different," Pai said, so variations are expected, depending on size of system, use, etc.

In an effort to keep up with consumer demand for ways to save money, Hawaiian Electric Co. also last week came out with 101 tips to save.

The booklet offers more than one energy-saving tip per day leading up to an energy awareness event scheduled for Oct. 11.

The booklet features a variety of energy efficiency and conservation tips to reduce energy use throughout your home, from lighting and water-heating to cooking, refrigeration, and home appliances and electronics.

Reach Robbie Dingeman at rdingeman@honoluluadvertiser.com or 535-2429.