The Housing Board has introduced a doors-and-sanitary fittings package for Build-To-Order (BTO) flats launched from September.
The package costs between $3,190 and $4,330, depending on the flat type.
Home owners say this scheme goes some way to address concerns about the cost of the HDB's doors-only package, which costs about $3,000 on average for four- and five-room flats.
Under HDB's Optional Component Scheme (OCS), buyers can opt to pay for extra finishes such as flooring and internal doors.
They pick their options when selecting their flat at HDB Hub, and can use their Central Provident Fund or mortgage loan for this.
The OCS includes an internal doors package that ranges from $600 to $3,080, depending on how big the flat is.
A set of five laminated semi-solid timber doors, for instance, costs $2,830 for BTO projects launched in March this year such as Fajar Hills and Clementi Ridges. At Punggol Opal, a project launched in July, the set costs $3,080.
This works out to $566 to $616 per door for four- and five-room flats.
However, suppliers say that similar quality doors can be got for about $230 each, including installation.
Best Industrial in Kaki Bukit Crescent, a specialist in timber doors, charges $230 for a laminated semi-solid door with a timber frame. A full timber door - solid with no coat - costs $200.
This package, which includes installation, works out to $1,150 for home owners, including HDB home buyers.
Yong Fang Doors in Upper Bukit Timah Road sells and installs timber doors at $330 each. UHome Interior Design in Upper Paya Lebar Road charges a similar rate and its doors come with a 15-month warranty.
Last month, the HDB offered a new package offering doors and sanitary fittings including wash basins, taps and shower mixers costing between $3,190 and $4,330.
Sanitary fittings have never featured in the OCS before.
An HDB spokesman said sanitary fittings were introduced to provide greater flexibility and to minimise wastage when buyers choose to customise their own fittings during renovation.
The market rate for taps ranges from $20 to $300. Sinks cost between $40 and $300 and shower mixers start below $100 and can go up to $500.
Some home buyers, like Miss L. P. Lim, 37, who is unemployed, said the doors-plus-sanitary-fittings deal makes the package more attractive.
She added that she was generally pleased with what HDB has on offer. "One is really paying for convenience. You don't have to worry about the basics because those are taken care of and it's hassle free for owners. All in all it works out to be quite a good deal."
An HDB spokesman said the doors are sourced from suppliers and it requires its suppliers to ensure good workmanship and finishes. The agency sets out detailed specifications for the installation, ironmongery and locksets of its doors. Its doors also go through a series of tests to ensure their durability.
"Installation works are carried out by professional contractors and supervised by a team of consultants. HDB also provides a one-year Defects Liability Period, during which all defective items, if any, will be rectified," he said.
He added: "As these standards are good practices and not regulations, it is likely the doors supplied by renovation contractors may not meet similar standards."
Mr Poh Chin Tiong, 54, the boss of Best Industrial in Kaki Bukit, said HDB owners typically buy doors that cost around $200 each.
"The doors installed at such a price add value to the house. But those on a tighter budget can opt for cheaper doors such as classic doors with hollow cores that we sell for about $100," he said.
Driving instructor Muhammad Suhaimi, 29, who bought a four-room flat in Yishun last year, said he is perplexed by the price disparity, a view echoed by most home owners The Straits Times spoke to.
"Why are private contractor rates cheaper? HDB is buying and installing in bulk. It doesn't make sense to me," said Mr Muhammad.
Ms Ivy Tang, 31, an executive in the container industry, said that HDB should flag and explain to home buyers the pros and cons of opting in or out of the doors scheme.
"HDB should pre-empt buyers who might opt in out of convenience, to do their own research and calculations, be it for flooring, doors or sanitary fittings," she said.
The HDB spokesman said optional components are generally popular among home buyers.
About 70 per cent of those who selected a flat in this year's January and March BTO sales exercises, for instance, opted for at least one item under the scheme - for either doors or flooring, or both.
He said: "Many buyers continue to select them as they do not then have to engage their own contractors to do the works later on."
Others such as Mr Musbah Hashim, 52, who is unemployed, said they have little choice but to opt in.
He bought a four-room flat in Choa Chu Kang two weeks ago. "We cannot pay private contractors cash up front, so we have to to opt in as the money can be deducted from our CPF," he said.
Self-sourced doors differ from what HDB has to offer, said Mr Toh Chee Boon, 40, the deputy director of China Construction, which is handling four HDB projects.
"HDB doors are firmer internally and more durable. Stringent checks are also in place to ensure that the doors installed are of good quality," he said.
Ultimately, consumers have a right to exercise their choice, said Mr Seah Seng Choon, the executive director of the Consumers Association of Singapore.
"Buyers need to determine if they are comparing apple to apple. If quality seems the same, they can always get their own private contractors at lower cost."