Hot water isn't available.
Don't worry, you won't freeze to death.
Considering location and price, it's a choice.
Address：Progoti Sarani (Nodda Bus Stand), Baridhara, Gulshan
<Hotel Al-Falah International>
The hotel is in walking distance from Hotel Amir.
It is closer to airport.
Room is simple, but looks clearn.
Hotel Al-Falah International
Budget：SG-400tk, DW-1,000tk/2,000tk(AC), TW-1,500tk, 4Bed-2,000tk
Regent Guest House
Address：House#100, Road#13/C, Block#E, Banani
＜Sky Park Guest House＞
This hotel is in Banani as well.
You will get Wifi and hot water, too.
My friends stayed there, and they said room was good.
However, they didn't get hot water in some days....so, "Inshallah".
Sky Park Guest House
Address：House#65, Road#15, Block#D, Banani
Accomodation in Dhaka is not cheap comparing with village and considering other prices.
If you want to get lower price, stay in Southern area.
If you want to get higher price?
Plenty of choices in Gulshan & Banani area!