My wife is a stay at home mom with 3 kids under 6 and but has rental income only at €10,300 less expenses and interest of €7,000 showing a profit of €3,300.
You cannot claim the Home Carers Tax Credit AND have your wife's rental income taxed at the 20% tax rate. You need to see which one is more beneficial to you and claim that one.
To have the rental income taxed @ 20% would be a PAYE liability of €3,300 @ 20% = €660
To have the rental income taxed @ 41% and claim the HCC would mean total PAYE payable of €3,300 @ 41% = €1,353 less the HCC of €810 would mean PAYE payable of €543
Therefore it's more tax efficient for you to have the rental income taxed @ the 41% rate AND claim the Home Carers Credit